About Shashank Expertise All SAS basic and macro prog. relatedquestionsI can answer.
I have masters degress in Statistics too. so i can also interprete the results.
Expert: Shashank Date: 11/15/2005 Subject: about a SAS problem
Question Thanks so much for your kind help. i know what does CI mean , in fact i have solve the problem (a)(b)(c) by using ANOVA test , i am now kind of confused what does the (d) mean , how to compute the CI for just one group 4, what does it compare to ? And how does it relate to f test?
the test requires us to use SAS program to do it .
Thanks a bunch !
Rachel
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Followup To
Question -
HI, shashank,
i am kind of desperate that i only have one day to finish the take home test:( thanks so mcuh for help me out. All problems are requried to use SAS code.
Pls see below:
1. A manufacturer of television sets is interested in the effect on tube conductivity of four different types of coating for color picture tubes. The following conductivity data are obtained.
Coating Type
1 143 141 150 146
2 152 149 137 143
3 134 136 132 127
4 129 127 132 129
(a) Is there a difference in the conductivity due to coating type? Use á=0.05
(b) Estimate the overall mean.
(c) Find an estimate of the difference between coating types.
(d) Compute a 95% confidence interval for the mean of coating type 4.
What does the question (d) mean , how can i interpert this?
thanks
Rachel
Answer -
we have to compute 95% CI considering all the observations,
I hope you know what is meant by confidence interval (CI).
It has upperbound and a lower bound, so we have to find a CI for mean of these observations such that out of 100 calculated means; 95 observed means will fall in this interval.
So you can particularly say about the effect on tube conductivity (this will the overall efeect as we are considering mean of all the observations)
If you want more help, you are welcome.
Shashank
Answer To comute 95%CI for colour we can use the following
L.B = (mean of obs.) - (((STDEV of obs.)/sqrt(# of obs.* Z (alpha/2))
U.B = (mean of obs.) + (((STDEV of obs.)/sqrt(# of obs.* Z (alpha/2))
Where u can get value of Z (alpha/2) from Normal tables.
# of obs= 4
mean of obs. = (139+127+132+129)/4
similarly you can calculate STDEV for 4 obs.
