# probability and statistics

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Chapter 9: 17. 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, M=4,S2=1.5 ; and for University
Z,M=6,S2=2.5. What should you conclude? Use the .05 level.
(a) Use the steps of hypothesis testing, (b) figure the effect size for the study;

• probability and statistics -

Here are a few hints:

Check out a one-way ANOVA for this kind of problem. Do the calculations to find the F-ratio to compare to the critical or cutoff value from the F-distribution table (used for ANOVA tests). Find the critical or cutoff value at .05 level of significance using the table to reject the null hypothesis (which would state that all population means are equal). If the null is rejected in favor of the alternate hypothesis (which would state that all population means are not equal), then you can conclude a difference.

• probability and statistics -

the cutoff is between 2 and 6