Question

A researcher at a college hears students complain that they don’t have enough time to in their week to study. He believes that the students at the college are spending much more time on Facebook, Twitter, and Instagram than they did three years ago. He knows that three years ago, the mean number of hours per week students spent of social media was 15.1 hours. He takes a sample of 16 students and finds they spend 23.3 hours per week on social media with SS=240.

a)Conduct a t-test to see is his theory is correct. (Be sure to show all 4 steps of a hypothesis test. Also be sure to consider if this is a one-tailed or two-tailed test.)

b)Measure effect size using Cohen's D.

c)Measure effect size using percentage of variance explained (r).

d)Estimate effect size by constructing 90% an confidence interval.

Answer 1

a)

The standard deviation is

b)

Cohen's d effect size is

c)

Effect size r2 is

d)

The 90% confidence interval is

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