In: Statistics and Probability
(Please show work/step-by-step. Must be legible.)
1. The researcher from the Annenberg School of Communications is interested in studying the factors that influence how much time people spend talking on their smartphones. She believes that gender might be one factor that influences phone conversation time. She specifically hypothesizes that women and men spend different amounts of time talking on their phones. The researcher conducts a new study and obtains data from a random sample of adults from two groups identified as women and men. She finds that the average daily phone talking time among 15 women in her sample is 42 minutes (with a standard deviation of 6). The average daily minutes spent talking on the phone among 17 men in her sample is 38 (with a standard deviation of 5). She selects a 95% confidence level as appropriate to test the null hypothesis.
a) How many degrees of freedom are there?
b) What is the obtained value of the test statistic (t)?
c) What is the critical value of the test statistic (t)? [t-obtained]
d) What decision should the researcher make about the null hypothesis? Be sure to explain your answer (e.g., what numbers provide the basis for this decision?).