For Exercises 49–56, do the following:

  1. State the hypotheses.
  2. Find and the critical region.
  3. Find . Also, draw a standard normal curve showing , the critical region, and .
  4. State the conclusion and the interpretation.

Question 9.84

49. Facebook Connections. According to Facebook.com, the mean number of community pages, groups, and events that users are connected to is 80. A random sample of 64 Facebook users showed a mean of 86 connections to community pages, groups, and events. Assume . Test, using level of significance , whether the population mean number of connections to community pages, groups, and events is greater than 80.

9.2.49

(a) (b) . Reject if . (c) .

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(d) Since is not , the conclusion is do not reject . There is insufficient evidence at the 0.05 level of significance that the population mean number of connections to community pages, groups, and events is greater than 80.