Question

The mean number of close friends for the population of people living in the U.S. is 5.7. An investigator predicts that the mean number of close friends for introverts will be significantly different than the mean of the population. The mean number of close friends for a sample of 26 introverts is 6.5. The standard deviation of scores in this sample is 1.3. Do these data support the investigator's prediction?

a. State the null and alternative hypotheses in symbolic form.

b. Set the criteria for making a decision. What are the critical values? 
(Use a = .01) 


c. Compute the appropriate test statistic. Show your work.

d. Based on your results, evaluate the null hypothesis. Circle One: Reject H0 e. State your conclusions in terms of the original research.

f. Compute Cohen’s d and interpret the effect (i.e., is it a small, medium, or large effect) g. Compute the 99% confidence interval for this study

Fail to Reject H0

Interpret the 99% confidence interval below.
We can be _______________________________________________________________ that, over repeated sampling, the

interval between____________________________________ and _________________________________________

contains the true population mean in _________________________________________________________ for

________________________________________________________________________________________________.

Answer 1