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.

20. State the null and alternative hypotheses.

H0: __________

Ha: __________

In symbols, what is the random variable of interest for this test?

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

Calculate the test statistic and p-value.

Find the p-value on TI- 84 Calculator

Does it appear that the means are the same? Why or why not?