posted by Charles on .
Do students at various universities differ in how sociable they are? Twenty-five
students were randomly selected from each of three universities in a region and
were asked to report on the amount of time they spent socializing each day with
other students. The result for University X was a mean of 5 hours and an estimated
population variance of 2 hours; for University Y, ; and for University
Z, . What should you conclude? Use the .05 level.
(a) Use the steps of hypothesis testing, (b) figure the effect size for the study;
and (c) explain your answers to parts (a) and (b) to someone who has never had
a course in statistics.
Data for the other two universities are not given. Test for the difference between means.
Z = (mean1 - mean2)/(standard error of difference between means)
SE diff. = sq.rt. (SE1^2 + SE2^2)
SE = standard deviation/sq.rt. (n-1)
SD = sq. rt. of variance
I'll leave the explanation up to you. From my experience in teaching, once you can explain the process to someone else, you will really understand it yourself. Good luck.