Answer:
The 95% confidence interval for the mean life expectancy of non-hispanic white males is (73.3 years, 79.3 years).
Step-by-step explanation:
This is the 95% confidence interval for the mean life expectancy of non-hispanic white males.
Our sample size is 100
The first step to solve this problem is finding our degrees of freedom, that is, the sample size subtracted by 1. So

Then, we need to subtract one by the confidence level
and divide by 2. So:

Now, we need our answers from both steps above to find a value T in the t-distribution table. So, with 99 and 0.025 in the two-sided t-distribution table, we have 
Now, we find the standard deviation of the sample. This is the division of the standard deviation by the square root of the sample size. So

Now, we multiply T and s

Then
The lower end of the confidence interval is the mean subtracted by M. So:

The upper end of the confidence interval is the mean added to M. So:

The 95% confidence interval for the mean life expectancy of non-hispanic white males is (73.3 years, 79.3 years).