Use the following informotion to answer the next 12 exercises: The U.S. Center for Disease Control reports that the mean life expectancy was \(47.6\) years for whites born in 1900 and \(33.0\) years for nonwhites. Suppose that you randomly survey death records for people born in 1900 in a certain county. Of the 124 whites, the mean life span was \(45.3\) years with a standard deviation of \(12.7\) years. Of the 82 nonwhites, the mean life span was \(34.1\) years with a standard deviation of \(15.6\) years. Conduct a hypothesis test to see if the mean life spans in the county were the same for whites and nonwhites.

Which distribution (normal or Student's t) would you use for this hypothesis test?

Use the following informotion to answer the next 12 exercises: The U.S. Center for Disease Control reports that the mean life expectancy was $47.6$ years for whites born in 1900 and $33.0$ years for nonwhites. Suppose that you randomly survey death records for people born in 1900 in a certain county. Of the 124 whites, the mean life span was $45.3$ years with a standard deviation of $12.7$ years. Of the 82 nonwhites, the mean life span was $34.1$ years with a standard deviation of $15.6$ years. Conduct a hypothesis test to see if the mean life spans in the county were the same for whites and nonwhites.

Which distribution (normal or Student's t) would you use for this hypothesis test?

For the mean difference in life span between whites and nonwhites, the hypothesis test employed Student's t distribution.