Facebook: A study showed that two years ago, the mean time spent per visit to Facebook was 20.8 minutes. Assume the standard deviation is 6 = 8.0 minutes. Suppose that a simple random sample of 107 visits was selected this year and has a sample mean of x = 18.8 minutes. A social scientist is interested to know whether the mean time of Facebook visits has decreased. Use the a=0.10 level of significance and the P-value method with the TI-84 calculator. (a) State the appropriate null and alternate hypotheses. (b) Compute the P-value. (c) State a conclusion. Use the a=0.10 level of significance. Part: 0 / 4 Part 1 of 4 (a) State the appropriate null and alternate hypotheses. Ho 00 0=0 H This hypothesis test is a (Choose one) test. X 5