Smartphone Battery Life. Battery life is an important issue for many smartphone owners. Public health studies have examined "low-battery anxiety" and acute anxiety called nomophobia that results when a smartphone user's phone battery charge runs low and then dies (Wall Street Journal, https://www.wsj.com/articles/your-phone-is-almost -out-of-battery-remain-calm-call-a-doctor-1525449283). Battery life between charges for the Samsung Galaxy S9 averages 31 hours when the primary use is talk time and 10 hours when the primary use is Internet applications. Because the mean hours for talk time usage is greater than the mean hours for Internet usage, the question was raised as to whether the variance in hours of usage is also greater when the primary use is talk time. Sample data showing battery life between charges for the two applications follows.

1) Provide a table of summary statistics and brief interpretation.

2) Test the claim that the difference in average battery life between talk time and internet usage time is 21 hours (31 for talk time vs 10 for internet usage).This should include the null and alternative, the test statistics, p-value, conclusion and interpretation.

3) Test whether the variance is also greater when the primary use is talk time.

This should include the null and alternative, the test statistics, p-value, conclusion and interpretation.