You are here:
- Home
- Science
- Mathematics
- Probability & Statistics
Probability & Statistics/Questions Answered by Expert ronny fisher
| Subject | Date Asked |
| sample size | 1/26/2012 |
| Q: Greetings Ronny, My name is Tetsu, a graduate student in ecology in Toronto, ON, Canada. All my ... A: tetsu - there is no magic sample size that works for all situations. what constitutes an adequate ... | |
| What method(s) do you suggests? or such method available? | 12/21/2011 |
| Q: First have new year wish all the best for all...(and at the beginning apologize for long mail and ... A: tahsin - it seems to me your investigation involves an experiment with [multivariate] 4x10 ... | |
| Two questions and a "Thank you" | 12/20/2011 |
| Q: Related to my theses, I have two statistics questions - and a "thank you" for you: 1) I wish to ... A: wing - first off - thank you for the blessing. now - as regarding your firstyour situation is ... | |
| Question | 12/9/2011 |
| Q: Ronny - If we wanted to evaluate the effectiveness of a predictor of corporate bankruptcy, would we ... A: chun - your answer looks ok to me. sometimes one does not have the capability to preselect from ... | |
| Parameter Optimization | 11/18/2011 |
| Q: Please let me rephrase my question. There is given the following Data (A_i, B_i) for i=1...n This ... A: edmund - in case 1, if either A or B [or both] are random [and independent] and if either [or ... | |
| Parameter Optimization | 11/15/2011 |
| Q: Please let me rephrase my question. There is given the following Data (A_i, B_i) for i=1...n This ... A: edmund - it will require a bit of time for me to deal with the entire problem you pose. so i will ... | |
| data dependetn hypothsis | 10/19/2011 |
| Q: http://en.wikipedia.org/wiki/Testing_hypotheses_suggested_by_the_data this is was i meant by post ... A: bastian - the usual technique for dealing with hypotheses suggested by the data is to use some sort ... | |
| Farkle Odds | 9/30/2011 |
| Q: My wife and I just started playing the game of spicy Farkle -- it has one red side on each of six ... A: al - the chance that all red faces come up on one roll of the 6 dice is indeed (1/6)^6. think of ... | |
| probability in poker | 9/21/2011 |
| Q: What is the probability of getting 4 aces in 5-card hand poker? A: ashley - the simple answer is this: if you are dealt 5 cards, the number of hands you could get ... | |
| statistical analysis question | 9/11/2011 |
| Q: I am currently completing analysis of data for reserach in linguistics. I've been researching this ... A: kate - let's see if i have this right: for each text [or, perhaps, timepoint], there are 7 ... | |
| statistical analysis question | 9/10/2011 |
| Q: I am currently completing analysis of data for reserach in linguistics. I've been researching this ... A: kate - you need to add more details for me. i gather the 7 measures are numerical and were derived ... | |
| too simple? | 9/7/2011 |
| Q: I came upon an interesting probabilistic assertion in a book I'm reading. Here's the quote: "Once ... A: tom - in both of your scenarios, the probability of a match is .01. you agree this is so for case ... | |
| What type of statistical test would you use to compare | 8/8/2011 |
| Q: Okay, I know you use a one-sample t test to compare an actual sample to a hypothetical value, and a ... A: nick - your last question points to the difficulty with testing for outliers. a number of plausible ... | |
| What type of statistical test would you use to compare "one observation" with a sample? | 7/25/2011 |
| Q: Okay, I know you use a one-sample t test to compare an actual sample to a hypothetical value, and a ... A: nick - your question is very interesting. at first, it seemed to me just a standard outlier ... | |
| Pinochle | 7/17/2011 |
| Q: What are the odds that a two person team will win 14 straight games against and equally rated team? ... A: ken - the odds against one of two equal teams winning 14 games in a row is 16383:1. here 16383 = ... | |
| Permutation with some alike objects | 7/11/2011 |
| Q: I have n objects where n1 are alike and n2 are alike. I take all n objects at a time. The ... A: Waisiu - i do not think in general there is a simple expression for the number of distinct ... | |
| Design testing using split/multivariate testing | 6/10/2011 |
| Q: Ronny Fisher, I am a user experience designer working on web and softwares. Recently i came to know ... A: Shivaprasad - you do indeed have a number of questions. let's start with some in part 1: in order ... | |
| statistics | 5/18/2011 |
| Q: I have the data of marks of 548 students in three different papers of mathematics, and i am suppose ... A: sakina - you can compare all 3 exams at once using a 1-way MANOVA test. [the 'M' stands for ... | |
| Sample size calculation | 5/6/2011 |
| Q: I have rephrased my question. I want to calculate the prevalence of transfusion transmitted viral ... A: Ozzanne - i understand you want to compare the prevalence of hiv in the two groups of blood. to ... | |
| Sample size calculation | 5/2/2011 |
| Q: I have rephrased my question. I want to calculate the prevalence of transfusion transmitted viral ... A: Ozzanne - let's take your queries one step at a time. you have two populations you wish to ... | |
| Stats Project - Movie Locations & Tourism Effects | 4/29/2011 |
| Q: I'm in a dilemma with my grad-level statistics project. My professor loves my research topic, and ... A: mc - your project sounds like it involves the behavior of a time-series, since the numbers of ... | |
| How to use regression when response is a continous data and predictors are binary | 3/21/2011 |
| Q: Respected Mr. Ronny I am social science researcher currently working on primary education. The ... A: jai - i misread your question. please disregard my previous response. i need a bit more ... | |
| Probability | 3/15/2011 |
| Q: If I roll an eight-sided numbered die eight times, what is the probability that no number comes up ... A: tj - the probability is 8!/8^8. the reason: any particular sequence of numbers in 8 rolls - with ... | |
| Significance Test | 3/9/2011 |
| Q: Following up on your response to my previous question - can you please elaborate a bit further? ... A: tudor - attached is a correction to the original attachment i sent previously, which, i believe, ... | |
| Significance Test | 3/4/2011 |
| Q: Can you please let me know it there is a statistical significance test that I can use on an ... A: tudor - i am attaching as a gif file an explanation of how to compare two sample ratios based on ... | |
| Significance Test | 2/22/2011 |
| Q: Can you please let me know it there is a statistical significance test that I can use on an ... A: tudor - there are inferential procedures for statistics that are ratios of sums or sample means. ... | |
| Stat question | 2/5/2011 |
| Q: I am presently researching: Research"Do people hold onto losing stocks longer than winning ... A: wing - i need some clarification about what you are thinking to do: 1. what do you mean by "at a ... | |
| Understanding data for assignment | 1/3/2011 |
| Q: I was hoping you could help me with identifying what type of data I am using before I run parametric ... A: aideen - in order to answer your questions, you need to tell me what sort of measurement of ... | |
| Regression analysis | 12/10/2010 |
| Q: Sir, I have a question on regression analysis. I am doing regression analysis of a group of data. ... A: ap - what you propose doing is entirely correct. the 0,1 quantities are called dummy variables and ... | |
| Simple & Weighted Averages | 12/8/2010 |
| Q: I am curious to know how to determine the weighted average by using a simple average. I am just ... A: kenneth - first of all - you are welcome. second - it would be possible to obtain the weighted ... | |
| almost a lifespan | 12/8/2010 |
| Q: I am having great problems analysing the results of my experiment. It is a survival assay, every ... A: ben - as i am not a biologist, some of your terminology is unfamiliar to me. perhaps you will ... | |
| Probability of success on successive attempts | 12/6/2010 |
| Q: I am trying to solve for probability given the same chance on successive attempts. For example, a ... A: mike - the chance of drawing a white marble as successive black ones are drawn and NOT replaced ... | |
| Sample Size | 11/30/2010 |
| Q: I have a question relating to sample size. I’m conducting an experiment (subject can respond to ... A: you may not be able to get a ME of +/- 5% with a sample size of < 30. altho, if the proportion you ... | |
| t-testing, and Z-score conversions | 11/18/2010 |
| Q: I am looking at a data series of Reaction Times for a number of variables. I am firstly doing a ... A: hannah - based on what you last wrote, my understanding of your data is this: you have 12 ... | |
| t-testing, and Z-score conversions | 11/17/2010 |
| Q: I am looking at a data series of Reaction Times for a number of variables. I am firstly doing a ... A: hannah - what you describe has the formal structure a 2x2x3 [12 cell] factorial experiment for each ... | |
| program evaluation- which anova to use? | 11/16/2010 |
| Q: I'm a grad student working on designing a program evaluation. It's been a few years since my last ... A: constantina - ok - i have a better picture of the experiment now. let's focus, for the moment, on ... | |
| program evaluation- which anova to use? | 11/15/2010 |
| Q: I'm a grad student working on designing a program evaluation. It's been a few years since my last ... A: constantina - i am not quite sure about what your data design looks like, so perhaps you will ... | |
| t-testing, and Z-score conversions | 11/14/2010 |
| Q: I am looking at a data series of Reaction Times for a number of variables. I am firstly doing a ... A: hannah - you don't say exactly what the different 'variables' are that you compare within [age] ... | |
| Deng's question | 10/14/2010 |
| Q: I was going to ask a follow up but it says too many follow ups and I need to ask a new question. ... A: deng - when i said "we are in trouble" - i was referring to the high percentage of resistant ... | |
| comparison of percentages | 10/13/2010 |
| Q: I am doing a study on bacterial Ampicillin resistance . We have 3 treatment (3 diets)and 6 pigs in ... A: deng - your experimental design is of a sort where ANOVA techniques are usually applied. such are ... | |
| Understanding Chance/Odds | 10/9/2010 |
| Q: I can't convince anyone about my theory on odds so I would like to try it on an expert. My theory ... A: joe - i think you are putting together two different notions about probability. one notion is the ... | |
| Understanding Chance/Odds | 10/9/2010 |
| Q: I can't convince anyone about my theory on odds so I would like to try it on an expert. My theory ... A: joe - i agree with part of what you say - but not all. you are correct that probability refers to ... | |
| My Daughter's Birthday | 10/7/2010 |
| Q: My daughter was born on 12-12-00 so in the year 2012 her birthday will be 12-12-12 and she will be ... A: stephanie - your daughter's birthday numbers do sound unusual. but it is difficult to say how rare ... | |
| Lotteries | 10/5/2010 |
| Q: Fisher; I am a student at Clear Brook High School doing a science fair project about simulating a ... A: rohan - you left out one critical part of the story: how many possible numbers can be drawn. [for ... | |
| comparison of percentages | 10/4/2010 |
| Q: I am doing a study on bacterial Ampicillin resistance . We have 3 treatment (3 diets)and 6 pigs in ... A: deng - sorry this reply is late - unforseen circumstances interfered. after looking at the data ... | |
| Estimators Qn and Sn | 10/4/2010 |
| Q: I'm technically a civil engineer who is not familiar with statistics! I'm looking for a robust ... A: keyvan - i am not familiar with the notation Qn. i will track it down from the references you cite ... | |
| comparison of percentages | 9/30/2010 |
| Q: I am doing a study on bacterial Ampicillin resistance . We have 3 treatment (3 diets)and 6 pigs in ... A: deng - you are dealing here with the difference between 'statistical significance' and 'practical ... | |
| Probability by percent | 9/24/2010 |
| Q: I was discussing probability with some colleagues of mine. The basic setup is that there is a random ... A: matthew - your intuition is not serving you well here. chances of repeated outcomes work like this: ... | |
| Further info | 9/22/2010 |
| Q: Further to my previous email, I will be carrying out the following: T-tests ANOVAs Chi-squared For ... A: nicole - the disparate sample sizes you have should not be a problem. in fact, the 'sample' for ... | |
| Odds where results must show unique values. | 9/17/2010 |
| Q: you seem to be active. Thank you very much in advance for your expertise. My question is one of ... A: neil - you pose the question this way: "What are the odds of getting a single target tech with say ... | |
| Odds where results must show unique values. | 9/10/2010 |
| Q: you seem to be active. Thank you very much in advance for your expertise. My question is one of ... A: neil - i have an answer for you - but i want to be certain it is to your actual question. so an ... | |
| positive matches | 9/7/2010 |
| Q: This is for testing the accuracy of OCR conversion of a document. If I want to be certain I have a ... A: steven - i'm not quite sure what you see when you talk about being able to match characters. does ... | |
| Probability mass function applicable or not? | 9/6/2010 |
| Q: you seem to be active. Thank you very much in advance for your expertise. My question is one of ... A: neil - please clarify for me just how a 'tech' gets closed out: can there more than one player ... | |
| what test should I use | 9/3/2010 |
| Q: I have a population of 42273 (average number of vehicles passing a fixed point per day. The average ... A: shannon - your referring to the number 42273 as a 'population [size]' is a bit misleading. a ... | |
| Risk vs Probablity | 8/27/2010 |
| Q: I am trying to figure out if I can use the 5 year risk calculated by ... A: isis - you can use the 5-yesr risk figure as a "pre-test" probability to do a formal calculation ... | |
| Comparing regression coefficients | 8/25/2010 |
| Q: I have a longitudinal data set. I want to find out the predictive relationship between an ... A: namtso - i think we've got to backtrack a bit. my 'understanding' of language as a 'covariate' was ... | |
| Comparing regression coefficients | 8/22/2010 |
| Q: I have a longitudinal data set. I want to find out the predictive relationship between an ... A: namtso - it may be that the structure of your data exhibits subtleties not usually found in ... | |
| Comparing regression coefficients | 8/20/2010 |
| Q: I have a longitudinal data set. I want to find out the predictive relationship between an ... A: namtso - i am trying to understand what you are really trying to find out. you state at the ... | |
| Interpreting correlation statistics | 7/29/2010 |
| Q: This is undoubtedly a very easy question but it's been a looooong time since I took stats... I've ... A: terry - one would interpret your results thus: since the 2-tail p-value for r is less than .05, ... | |
| regression with algged variables | 7/18/2010 |
| Q: I am building a lagged regression model and wan to have two suggestions from you. First, if i level ... A: mark - it is not clear to me from what you write exactly what you are dealing with. perhaps you ... | |
| hypothesis testing with correlated samples | 7/17/2010 |
| Q: Introduction: I am currently working with a class of algorithms called Markov chain monte carlo ... A: kristoffer - i haven't forgotten your question. i have been doing a bit of investigating to see ... | |
| hypothesis testing with correlated samples | 7/14/2010 |
| Q: Introduction: I am currently working with a class of algorithms called Markov chain monte carlo ... A: kristoffer - i am preparing a somewhat more detailed reply for you. but i just want to be sure i ... | |
| hypothesis testing with correlated samples | 7/12/2010 |
| Q: Introduction: I am currently working with a class of algorithms called Markov chain monte carlo ... A: kristoffer - your question is certainly non-trivial. some fragmentary thoughts are given below - ... | |
| Selecting an answer from all the right answers | 7/11/2010 |
| Q: On NPR (radio programs) they occasionally have a puzzle for the audience to solve. They say that ... A: urania - you are absolutely correct that just repeatedly selecting from ALL submitted answers at ... | |
| The odds of #'s | 7/5/2010 |
| Q: Would anyone's chances of winning the lottery be higher or lower if they played the same numbers ... A: sterling - in an ideal world, it should make no difference which number[s] you play each time. the ... | |
| Likert scale analysis | 7/2/2010 |
| Q: Sir m working on a project "Recruitment Challenges in BPO sector" for this I have designed a ... A: priyanka - a bar chart would be a useful presentation of such data. it might help bring out the ... | |
| Likert scale analysis | 6/30/2010 |
| Q: Sir m working on a project "Recruitment Challenges in BPO sector" for this I have designed a ... A: priankya - before arriving at an appropriate method of analysis, you need to provide some idea[s] ... | |
| Likert scale analysis | 6/28/2010 |
| Q: Sir m working on a project "Recruitment Challenges in BPO sector" for this I have designed a ... A: namastai priyanka - it would be possible to use a t-test on likert scale data and implement it in ... | |
| pairing | 5/30/2010 |
| Q: I am studying whether two types of cells (type a and b) are clustered separately from each other, or ... A: yoshi - to paraphrase your question, you are interested in knowing if the observed pairings among ... | |
| Hard Solve a small game | 5/25/2010 |
| Q: I have been playing the game of 24 since I was a little kid (Unfortunately, it has also been that ... A: anthony - i'm not sure what you mean by saying "guarantee the problem unsolvable". the problem ... | |
| Hard Solve a small game | 5/24/2010 |
| Q: I have been playing the game of 24 since I was a little kid (Unfortunately, it has also been that ... A: anthony - there are a few things about your question that are unclear. perhaps the foremost one ... | |
| Setting Up a Problem in Absentee Predictions | 5/22/2010 |
| Q: I want to try and predict absenteeism in a school. Unfortunately, I'm the English teacher. LOL. In ... A: terry - it might be possible to predict which students are heading for a fall [or should that be 'a ... | |
| Significance? | 5/19/2010 |
| Q: Let's say you were comparing a battery of test scores male vs. female. On each of the 50 tests, the ... A: will - when you use the term "insignificant", is it in its usual or colloquial sense meaning "of ... | |
| statistics for experiments | 5/16/2010 |
| Q: I am testing the response of a single group of insects 2 different food sources. Each insect can ... A: kat - if there were no preference for the two foods, you would expect to see a 50-50 split among ... | |
| Baseball Probability | 5/15/2010 |
| Q: What are the mathematical odds of one team losing to another team by the exact same scores? This ... A: jack - your question is at the same time both straightforward and difficult to answer. the ... | |
| Pinochle: probabilities the one card you need will be in partner's hand | 3/13/2010 |
| Q: In a single deck pinochle game (48 card standard pinochle deck, there are two each of 24 cards; and ... A: david - let me give you an example of how to obtain the sort of probabilities you want: i will use ... | |
| Repeating lotto numbers | 3/12/2010 |
| Q: The CA Lotto has the numbers 1-27 for it's mega winning numbers. When I purchase tickets for my ... A: ken - the chance the 5 weekly numbers will all be different is q = 26/27 x 25/27 x 24/27 x 23/27 ... | |
| Bartlett's Test and Mann's Test | 3/12/2010 |
| Q: I would like to create an excel spreadsheet that allows me to test a set of data if it fits a ... A: germaine - i don't think plain vanilla excel can do the goodness-of-fit tests you want. there are, ... | |
| pool odds | 3/5/2010 |
| Q: If I have a square in an ncaa tournament pool, what are my odds of winning one game? Two? etc... ... A: mike - you have a particular case of what is called a binomial distribution. it generally applies ... | |
| estimate model parameter from data | 3/3/2010 |
| Q: this advection-diffusion type model simulates path lengths x[i,,] for nind individuals using a ... A: julie - i gather you are using R to do the simulations. [please confirm.] some questions: 1] are ... | |
| Follow up | 2/25/2010 |
| Q: I posted a follow-up to your posting, but I'm not sure if it registered. Let me know if it didn't ... A: becky - it sounds as tho you got the q-q plots right. i would like to see the results. as you ... | |
| Follow up | 2/25/2010 |
| Q: I posted a follow-up to your posting, but I'm not sure if it registered. Let me know if it didn't ... A: becky - for some reason, i apparently have not been receiving the followup messages you have been ... | |
| Analysing data sets | 2/22/2010 |
| Q: For my dissertation, i am preparing benchmarks for Financial Ratios like Return on Investment, etc. ... A: mahesh - no doubt the relevance of the outputted values of chi-squared etc. can be explained. but ... | |
| Analysing data sets | 2/21/2010 |
| Q: For my dissertation, i am preparing benchmarks for Financial Ratios like Return on Investment, etc. ... A: mahesh - let me first try to clarify a point or two: regarding the results for the kw test [or ... | |
| Normal Distribution | 2/16/2010 |
| Q: I didn't know if I needed to post as a new question or as a reply to you. So I'm doing both. Here ... A: becky - after your second communication, i'm not exactly sure what the question[s] is[are]. i can ... | |
| Analysing data sets | 2/15/2010 |
| Q: For my dissertation, i am preparing benchmarks for Financial Ratios like Return on Investment, etc. ... A: mahesh - let me first state that the arcana of financial mathematics is not something i am ... | |
| statistics | 2/11/2010 |
| Q: I know just enough about statistics to be dangerous, but not enough to be able to justify ... A: becky - your question sounds interesting. before delving further into dealing with outliers - which ... | |
| Question about size | 2/10/2010 |
| Q: There are potential market segments of size 64,927 and 59,028 respectively. Instead of mailing all ... A: wing - the sample size actually does depend on the population size. the formula i gave you has the ... | |
| choosing the proper statistical test | 2/9/2010 |
| Q: The question is fairly straight forward. I have two different sets of independent, continuous data ... A: tom - there was an unfortunate inaccuracy in my first reply about using the WMW test. i am ... | |
| choosing the proper statistical test | 2/8/2010 |
| Q: The question is fairly straight forward. I have two different sets of independent, continuous data ... A: tom - with small samples especially, i would suggest first eyeballing the data with a normal q-q ... | |
| Figuring probabilities | 2/7/2010 |
| Q: I am interested in finding out how I could determine the probabilities and expected returns for the ... A: sean - sorry to have temporarily disappeared. personal matters required some attention. I am ... | |
| Figuring probabilities | 2/5/2010 |
| Q: I am interested in finding out how I could determine the probabilities and expected returns for the ... A: sean - i need a bit more clarification about item 4: can you be more specific about the '125 data ... | |
| choosing the proper statistical test | 2/4/2010 |
| Q: The question is fairly straight forward. I have two different sets of independent, continuous data ... A: thomas - t-tests are routinely done with samples of size 5 or so. that t-tables start with degrees ... | |
| Figuring probabilities | 2/2/2010 |
| Q: I am interested in finding out how I could determine the probabilities and expected returns for the ... A: sean - first - a disclaimer: i am not an expert in financial maths and things of that nature. ... | |
| Probability with multiple dice rolls | 2/1/2010 |
| Q: I'm trying to determine the probability of multiple dice rolls when the successes are cumulative. ... A: andrew - i can give you an answer or two to your question. but first, let me mention that your ... | |
| statistics | 2/1/2010 |
| Q: . Our team is making actually making a thesis and sadly previous stats classes in our school didn't ... A: monique - i will try to help - at least to give you a push in the right direction. without knowing ... | |
| stats | 1/31/2010 |
| Q: I am having a difficult time differentiating between nominal and ordinal levels of measurement. I ... A: martha - your question does point out that there can be some degree of ambiguity in the designation ... | |
| statistics | 1/30/2010 |
| Q: does each team have the same chance of winning the world cup? in terms of probability assuming we ... A: daniel - it would seem, on its face, tht your friends are correct. if the teams are equally ... | |
| General Q on Stats/Probabilty | 1/29/2010 |
| Q: I need to analyse data from Retail Customers at a major retailer here in South Africa. (All ... A: alan - i am not sure that your proposed sampling scheme - selecting only H-people [as it were] - is ... | |
| Type of analysis | 1/27/2010 |
| Q: I am new to Statistics however I need to use them to analyze experiments I have carried out. I have ... A: audrey - on its face, it would appear that your experiment is a 4-factor factorial design, the ... | |
| Probability with multiple dice rolls | 1/26/2010 |
| Q: I'm trying to determine the probability of multiple dice rolls when the successes are cumulative. ... A: andrew - your questions sound fairly complex. i think it may be best to go at dealing with them one ... | |
| Analysis of non-likert type scales | 1/25/2010 |
| Q: I am involved in a project in which we ask participants to rate their medication taking. We are ... A: karina - it is not uncommon to assign numerical values to an ordinal response such as the one you ... | |
| Is there a way to test for Partial Correlation if there's a Nonlinear Correlation? | 1/24/2010 |
| Q: Maybe I'm weird, but I like to read peer-review journals for fun although I'm not a researcher nor ... A: nick - curvilinear regression for one response [y] and one explanatory variable [x] can be done by ... | |
| Question about size | 1/19/2010 |
| Q: There are potential market segments of size 64,927 and 59,028 respectively. Instead of mailing all ... A: wing - the sample size needed to determine the response rate depends on how precise an estimate you ... | |
| standard deviation of sample plots | 1/19/2010 |
| Q: I have a question about calculating the standard deviation of some tree growth data from a ... A: ross - the SD for each treatment should be calculated from the 3 sample totals or means of the ... | |
| Hurst exponents | 1/18/2010 |
| Q: Well, in a Wiener process, because you want to keep the same noisy characteristics, no matter how ... A: javier - i'm not entirely sure what you are asking - but perhaps this will be of some help: a ... | |
| Combination probs | 1/14/2010 |
| Q: Can you tell me how many combinations of 8 numbers are possible in numbers from 1 til 75? A: anamaria - sorry to have 'brushed you off' as an undergraduate seeking help with homework. no ... | |
| Standard Error and Statistical Significance | 1/12/2010 |
| Q: I have a 2004 estimate (from plot samples) that there were 1.93 million trees in Washington, DC. ... A: mike - your intuition is ok, but the procedure you suggest is not quite what should be done. if ... | |
| poker probability | 1/7/2010 |
| Q: I was wondering how you calculate the odds that out of 7 randomly dealt cards, 5 will be of the same ... A: james - the calculation goes like this: the question is the same as asking for the probability ... | |
| Discrete Distribution | 12/31/2009 |
| Q: Could you please suggest me if the following is a Poisson/Binomaial.The incidence rate is 0.1 per ... A: siddarth - your question does not really make sense. also - it seems to be a homework question. ... | |
| Regarding interpretation of chi square test result | 12/28/2009 |
| Q: I have a question regarding post hoc test result for chi square test. I have a dichotomous DV and ... A: oko san - i gather you are working with a 2x3 table. please correct me if this is not the case. it ... | |
| Chi-square diagnostics | 12/18/2009 |
| Q: I'm trying to understand how to apply chi-square. This is how my simple mind has summarized. Am I on ... A: jawon - the assertions in your message are correct. looking at the odds ratio [o.r.] for a 2x2 ... | |
| interval estimation | 12/13/2009 |
| Q: in an interval estimation question.the formula says mean plus t0.05(v)times standard deviatin ... A: nashwa - one should, in principle, always use the values from the t-table. however, if n >= 30 [or ... | |
| Healthcare Quality Data Reporting | 12/11/2009 |
| Q: A local healthcare quality reporting group collects claims based (electronic) data on various ... A: nate - your clarification is indeed helpful [to me]. the inaccuracy you describe is underreporting; ... | |
| Likert | 12/6/2009 |
| Q: sorry, a more refined question. Apart from calculating the mean scores for Likert items, which ... A: lindsey - the ME [= margin of error] that one attaches to an observed proportion to get a CI ... | |
| Healthcare Quality Data Reporting | 12/6/2009 |
| Q: A local healthcare quality reporting group collects claims based (electronic) data on various ... A: nate - i am not quite clear about some of what you wrote. what does it mean to say that "their data ... | |
| collision probability | 12/4/2009 |
| Q: did probability at college but have trouble applying to real world problems. i have a device that ... A: francis - can you send me the reference for the needle/pencil problem you cite? ronny ps: i ... | |
| Likert | 12/4/2009 |
| Q: sorry, a more refined question. Apart from calculating the mean scores for Likert items, which ... A: lins - i am not entirely sure what you are asking in your two posts. but you do seem to have some ... | |
| collision probability | 11/27/2009 |
| Q: did probability at college but have trouble applying to real world problems. i have a device that ... A: francis - the problem you pose seems like a research question. it may, however, have have been ... | |
| Stats, accidental sampling and the law | 11/23/2009 |
| Q: I have been accidentally sampled before (twice). I go along with the survey the sampler throws at ... A: ruairi - as i do not conduct surveys in the UK, i can only speculate as to why people under age 16 ... | |
| probability | 11/16/2009 |
| Q: How are you? I know that if there are two events that both have a probability of 0.5, then the ... A: andres - if the lift for A and B is 2, but for A, B and C it is 4, you can assume that C is somehow ... | |
| probability | 11/15/2009 |
| Q: How are you? I know that if there are two events that both have a probability of 0.5, then the ... A: andres - you are correct that for 3 independent events, each having probability 0.5, the ... | |
| Error analysis in linear regression | 11/15/2009 |
| Q: I am preparing for practical round in Physics Olympiad, and now I have problems understanding the ... A: chen - i am not familiar with ther expression you call delta m. in particular, i have never seen ... | |
| Deciding which statistical test(s) to use | 11/9/2009 |
| Q: I have a dataset which contains two variables: observations of precipitation and precipitation as ... A: steve - your question does seem to involve testing two hypotheses - and i think your formulation of ... | |
| counting statistics | 11/5/2009 |
| Q: I have a question about standard deviation of a number. When we plate cells in biology and we decide ... A: not being a biologist, i do not know what is meant by 'plating cells'. in order to give a cogent ... | |
| New Studentized Range table? | 11/2/2009 |
| Q: Good day! I just want to ask if the table used for the Tukey's test which is the studentized range ... A: mamoy - i haven't heard of 'new studentized range' tables per se. but there is an article that ... | |
| Computing Margin of Error | 11/2/2009 |
| Q: This is a follow-up to a previous question for which you helped me, thanks again for that. The ... A: dave - you are quite correct that the ME should also take into account the population size. the ... | |
| non gaussian distribution | 10/22/2009 |
| Q: Just read another article by Nicholas Nasser Taleb about fat tail distributions. I'll just copy and ... A: mark - the counter-intuitiveness you express about 'rare events' [which are called tail events in ... | |
| non gaussian distribution | 10/21/2009 |
| Q: Just read another article by Nicholas Nasser Taleb about fat tail distributions. I'll just copy and ... A: mark - sorry for the rejection email that went out to you. it was sent inadvertently. the ... | |
| Standard Deviation | 10/16/2009 |
| Q: I'm taking a Business Statistics course. I'm trying to understand the concept of standard ... A: davis - your question is more properly addressed to the instructor of the course you are taking - ... | |
| Countings of a categorical variable at different time points | 10/14/2009 |
| Q: Fisher, maybe you can help me with the following data. I´m not sure how to analyze them. Here is ... A: mara - i have an additional reference for you that may be of help. there is a book called ... | |
| Game odds | 10/9/2009 |
| Q: I asked this question earlier today but did not get an answer. Thought I may have not sent it ... A: ed - i can perhaps give you a push in the right direction to help you with your question. the ... | |
| Polynomial Equations And Method Of Least Squares | 10/5/2009 |
| Q: First and foremost I have been out of school awhile and my memory of statistics is hazy at best but ... A: barry - the attachment did get thru this time round. but unfortunately, it is of such poor quality ... | |
| Probability | 10/2/2009 |
| Q: However, I'm 35 years old and looking to broaden my expertise into lean / Six Sigma. One of the ... A: nathan - you've got a bit of a row to hoe if you want to become better acquainted with 6 sigma and ... | |
| Polynomial Equations And Method Of Least Squares | 10/1/2009 |
| Q: First and foremost I have been out of school awhile and my memory of statistics is hazy at best but ... A: barry - unfortunately, the attachment sent with your question did not seem to get transmitted to ... | |
| Percentages & Statistics | 9/28/2009 |
| Q: This is not a homework question! I am just curious to know how to solve this with a somewhat simple ... A: kenneth - there are lots of curious phenomena that one encounters in the realm of mathematics. for ... | |
| Percentages & Statistics | 9/26/2009 |
| Q: This is not a homework question! I am just curious to know how to solve this with a somewhat simple ... A: kenneth - your question involves simple algebra and is not really a probability question. having ... | |
| Analyzing a survey | 9/20/2009 |
| Q: I have a temporary consulting job analyzing the results of a survey taken at a large organization. ... A: dave - it sounds as though you do have a bit of a challenge facing you - to "just analyze it ... | |
| The statistical significance of a difference of 1.2 years between the UK and US life expectancies? | 9/12/2009 |
| Q: Can you help me better understand the following issue? US life expectancy - 78.2 UK life ... A: randy - there may be no statistical issues involved here. it all depends on how the life expectancy ... | |
| Statistics | 9/12/2009 |
| Q: In the results of a research study, an author says that a group of treated patients was more likely ... A: jeff - the abbreviation O.R. is not standard in statistics, as far as i am aware. it could mean ... | |
| Lotto Probabilities | 9/10/2009 |
| Q: When looking at the probability of picking numbers for the lottery is there any statistical ... A: randall - it makes no difference what system you use to pick numbers from week to week. if you ... | |
| Statistics | 9/7/2009 |
| Q: Do you happen to know if there is a excel program that I can use to tell me what numbers come up the ... A: chris - this is a somewhat outside my area of expertise. but for what it is worth, there is a ... | |
| Exponential Distribution | 9/6/2009 |
| Q: I'm taking a course in computer simulation. I have a few questions on exponential distribution. I've ... A: amril - the standard exponential distribution has the pdf f(x) = exp{-x} for x > 0. this ... | |
| Exponential Distribution | 9/5/2009 |
| Q: I'm taking a course in computer simulation. I have a few questions on exponential distribution. I've ... A: amril - the terms "exponential distribution" and "negative exponential distribution" mean the same ... | |
| lotto probability debate | 9/4/2009 |
| Q: I don't play the lotto, but recently there was a MA lotto with a really big payout and two friends ... A: megan - you are of course quite correct. any particular set of five numbers is as likely to occur ... | |
| F & t tests | 8/17/2009 |
| Q: In trying to verify a set of test results using the F & t tests. The F test which checks the ... A: phil - you have to describe the F-test you are trying to carry out in a context. F-tests are used ... | |
| F & t tests | 8/13/2009 |
| Q: In trying to verify a set of test results using the F & t tests. The F test which checks the ... A: phil - what you point out is that tests based on small samples can have low power (= the chance of ... | |
| Ouija Board Dice Test | 8/13/2009 |
| Q: I have a weird question for you. I am trying to come up with a way of testing the validity of an ... A: jim - your answer is correct if you take the sequence order of the dice into account - as if you ... | |
| Probability at least one of three cards will come out on a three card flop | 8/11/2009 |
| Q: I play poker regularly. In Hold'em there is what is called the 'flop', three community cards which ... A: rick - i understand your question to mean: what is the chance that at least one of the three cards ... | |
| Time series data | 7/29/2009 |
| Q: What does it mean to used pooled data to find the average autocorrelation coefficient for sales ... A: sally - time series is not exactly my thing. but i may be able to nudge you a bit in the right ... | |
| Minimum Sample | 7/27/2009 |
| Q: If i have a very large bucket of several thousand balls. All I know is that almost all the balls are ... A: mike - your question is actually the classic sample survey problem. the balls in the bucket ... | |
| Minimum Sample | 7/27/2009 |
| Q: If i have a very large bucket of several thousand balls. All I know is that almost all the balls are ... A: mike - let's be clear about one thing straightaway: there is no sampling scheme that will allow you ... | |
| Minimum Sample | 7/25/2009 |
| Q: If i have a very large bucket of several thousand balls. All I know is that almost all the balls are ... A: mike - the sort of answer you want is not clear. in particular, the sentence you wrote: "Im ... | |
| probability | 7/22/2009 |
| Q: The prize is behind one of three doors and you select door 1 of 3, and are later told that door ... A: frank - your problem is a classic example of paradoxical probability. it has been discussed by many ... | |
| Calculating the P value | 7/15/2009 |
| Q: I usually know how to go about getting the P value but this example threw me off. If I have a random ... A: one can test that null hypothesis that p = .22, rather than that it is <= .22, of course. but your ... | |
| Calculating the P value | 7/14/2009 |
| Q: I usually know how to go about getting the P value but this example threw me off. If I have a random ... A: one might infer from the word "only" in the question that what is wanted here is a one-sided test, ... | |
| measurement uncertianty | 7/13/2009 |
| Q: I need to calculate uncertainty between two sets of values like given below please tell me the ... A: syed - what you mean by "uncertainty" is unclear. i assume the standard values are fixed - not ... | |
| Mean of medians? | 7/10/2009 |
| Q: I've collected some reaction time data (i.e., how many milliseconds it takes to respond to a ... A: tim - let me be sure i understand your scenario: you have 4 blocks for each of, say n subjects. i ... | |
| combinatoric problem | 7/9/2009 |
| Q: You flip a coin 10 times. How many possible outcomes are there if you will not count the outcomes ... A: samantha - i do not usually answer homework type questions - but your problem is a bit unusual - in ... | |
ronny fisher
Top Expert on this page
Expertise
general questions on probability and statistics. please do not send intro prob/stat homework questions.
Experience
have taught probability and stats for 25 years
Education/Credentials
ba in math, phd in stats
Past/Present Clients
federal government, state AG, start-up pharma companies, engineering consulting firms, academic researchers (the list goes on).
©2012 About.com, a part of The New York Times Company. All rights reserved.