43. Facebook Friends. According to Facebook.com, the mean number of Facebook friends is 130. Suppose a sample of 100 Facebook users has a mean number of 110 Facebook friends, with a standard deviation of 50. Test whether the population mean number of Facebook friends is less than the reported 130, using level of significance .
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Critical-value method: . . Reject if . . Since is , the conclusion is reject . There is evidence at the 0.05 level of significance that the population mean number of Facebook friends is less than 130. method: . Reject if . . . Since the is , the conclusion is reject . There is evidence at the 0.05 level of significance that the population mean number of Facebook friends is less than 130.