Facebook: A study showed that two years ago, the mean time spent per visit to Facebook was 20.1 minutes. Assume the standard deviation is 6 = 7.0 minutes. Suppose that a simple random sample of 103 visits was selected this year and has a sample mean of x = 22.1 minutes. A social scientist is interested to know whether the mean time of Facebook visits has changed. Use the a = 0.05 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 = 0.05 level of significance