Test Hypotheses About a Population Mean with Known Using Confidence $\$ 192$

Short Answer

Test Hypotheses about a Population Mean with Known Using Confidence Intervals
-A group of 40 homeowners showed that their average monthly gasoline bill was $\$ 192$ with a standard deviation of $\$ 8$ . According to a national consumer group, their mean bill should be $\mu = \$ 188$ . Test this hypothesis by constructing a $95 \%$ confidence interval for the population mean.