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Probability & Statistics/Questions
| Subject | Date Asked | Expert |
| sample size | 1/26/2012 | ronny fisher |
| 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 | ronny fisher |
| 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 | ronny fisher |
| 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 | ronny fisher |
| 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 | ronny fisher |
| 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 | ronny fisher |
| 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 ... | ||
| Doubts about how to resolve this problem | 10/30/2011 | Michael Abrams |
| Q: I think that this problem could be resolved by combinations on the first question, and by ... A: That's exactly how to solve them. a) There are 52_C_6 ways of choosing 6 out of 52 items. ... | ||
| Consitency | 10/26/2011 | Michael Abrams |
| Q: Is the following consistent or not? Why or why not? μ-hat = (N - 1) * X-bar / N Thanks a lot ... A: Review the def. for a consistent estimator in the Wikipedia: In statistics, a sequence of ... | ||
| data dependetn hypothsis | 10/19/2011 | ronny fisher |
| 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 ... | ||
| Can't figure this out | 10/8/2011 | Michael Abrams |
| Q: Perhaps I am having a bad night and my brain doesn't want to figure this out. But I just can't (math ... A: If an event happens to .08% of the population, if only one event happens to each person, and if each ... | ||
| Sensitivity and specificity | 10/7/2011 | Michael Abrams |
| Q: I am a gastroenterologist with a question regarding predictive value. If a 42 yo patient has a ... A: CORRECTING THAT LAST LINE... This is an exercise in conditional probabilities. We have: P(+|C) = ... | ||
| paired and unpaired experiment | 10/3/2011 | Michael Abrams |
| Q: i have some doubts about the following: In performing a comparative experiment, the investigator ... A: In the case of the unpaired test, the (normalized) difference in the sample means is distributed as ... | ||
| Farkle Odds | 9/30/2011 | ronny fisher |
| 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 | ronny fisher |
| 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 ... | ||
| Statistics | 9/16/2011 | Michael Abrams |
| Q: Michael, I am trying to understand how to determine if a the data given in a study has a normal ... A: Knowing the mean and standard deviation by itself gives no indication of normality. Creating a ... | ||
| Mean vs Median | 9/13/2011 | Michael Abrams |
| Q: Im just wondering, is mean or median a better representation of an average? I have been told that ... A: The mean is just the technical name for the average, which is the sum of the values divided by the ... | ||
| statistical analysis question | 9/11/2011 | ronny fisher |
| 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 | ronny fisher |
| 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 | ronny fisher |
| 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 ... | ||
| Two out of Sixteen | 9/2/2011 | Michael Abrams |
| Q: There are sixteen doors and there is a prize behind two of them. If i am allowed two guesses, and i ... A: This is a simple exercise in conditional probability. P(guessing both doors correctly) = ... | ||
| Markov Chain | 8/16/2011 | Michael Abrams |
| Q: Hope you could help me out with this question. Say, a markov chain with {Xn:n=1,2,...} and with ... A: Start with the definition from Wikipedia: "A state i has period k if any return to state i must ... | ||
| What type of statistical test would you use to compare | 8/8/2011 | ronny fisher |
| 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 | ronny fisher |
| 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 | ronny fisher |
| 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 = ... | ||
| statistic | 7/12/2011 | Michael Abrams |
| Q: How can I determine say the average number of windows per building in a given city? Please provide ... A: The average number of windows per building can be used by taking a substantial random sample of the ... | ||
| Permutation with some alike objects | 7/11/2011 | ronny fisher |
| 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 ... | ||
| Correlation vs histogram, which is a better tool? | 7/8/2011 | Michael Abrams |
| Q: I have to investigate link between loan payment default probability and a loan candidate's wages. ... A: That's hard to say, a priori. It seems both tools could be useful--each complementing the other. ... | ||
| Linear Programming | 6/25/2011 | Michael Abrams |
| Q: A manufacturer wants to maximize the profit of two products. Product I yields a profit of $ 1.50 ... A: Your equations seem right. Now, graph the corresponding equalities (which are lines), namely: x+y ... | ||
| Siblings born same day one - one year apart | 6/22/2011 | Michael Abrams |
| Q: My Mother gave birth to my brother on my first birthday. I was born June 19, 1952 and he was born ... A: To estimate this, you would need to get a random sample of, say, 10,000 pairs of siblings from the ... | ||
| Statistics Question | 6/11/2011 | Michael Abrams |
| Q: Kelly recorded the length of time 48 teachers took to travel to school on Monday. The table shows ... A: The median divides the 48 teachers into two equal groups of 24, one representing those with the ... | ||
| Design testing using split/multivariate testing | 6/10/2011 | ronny fisher |
| 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 ... | ||
| probability and sample variance | 5/30/2011 | Michael Abrams |
| Q: Hope you can help me out with this simple statistic question. Assume that Xi are independent and ... A: I'll refer you to the article "Variance" in Wikipedia: "Distribution of the sample variance "Being ... | ||
| probability | 5/22/2011 | Michael Abrams |
| Q: I'm having trouble helping my 5th grader with math. If I have 5 flavors of ice cream, how many ... A: This is a simple example of combinations, where you're finding the number of ways of choosing 3 ... | ||
| statistics | 5/18/2011 | ronny fisher |
| 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 ... | ||
| Connections among particles in the observable universe | 5/7/2011 | Michael Abrams |
| Q: Remember the sort of problem where there are six people at a party and you want to know how many ... A: If for n things there are (n-1)*(n-2)*...*2*1= (n-1)! connections, then for 10^80 things there are ... | ||
| Sample size calculation | 5/6/2011 | ronny fisher |
| 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 ... | ||
| statistics | 5/4/2011 | Michael Abrams |
| Q: i dnt no how to distinguish a parameter and statistic. if a manager surverys a smple of of 100 ... A: The mean travel time is a statistic. A statistic is any function of the sample data, which in this ... | ||
| Sample size calculation | 5/2/2011 | ronny fisher |
| 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 | ronny fisher |
| 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 ... | ||
| p value or P? | 4/19/2011 | Michael Abrams |
| Q: Abrams, I have a few questions regarding p value or P in statistics. Throughout my grad school ... A: 1) The p-value is the probability of getting data as extreme [that is, as contradictory to the Ho] ... | ||
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).
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