stats word problem

Question

A researcher is interested in finding a 95% confidence interval for the mean number of times per day that college students text. The study included 120 students who averaged 37.2 texts per day. The standard deviation was 18.9 texts. Round answers to 3 decimal places where possible.

a. With 95% confidence the population mean number of texts per day is between ____ and ___texts. 

b. If many groups of 120 randomly selected members are studied, then a different confidence interval would be produced from each group. About ____ percent of these confidence intervals will contain the true population number of texts per day and about _____ percent will not contain the true population mean number of texts per day. 

Answer 1

Jessica, you can find the solution to your question below. If you have any questions, don't hesitate to reach out.

At 95% confidence :

1-95 = 0.05

0.05 ->alpha

120 ->. students

xbar -> 37.2

S.D. -> 18.9

critical value is 18.9/√120 = 1.725 and z score for 95% confidence is 1.96

so, 37.2 ± 1.96 •1.725

37.2 ± 3.381

Texts per day is 33.819 - 40.581.

B. 95% and 5%

I hope this helps answer your statistics question!