Insurance companies track life expectancy information to assist in determining the cost of life insurance policies. Last year the average life expectancy of all policy holders was 77 years. An insurance company wants to determine if their clients now have a longer life expectancy, on average, so they randomly sample 20 of their recently paid policies. The sample has a mean of 78.6 years and a standard deviation of 4.48 years. What is the value of the statistic?
A. 2.176
B. 1.597
C. 1.987
D. 2.355
E. 1.896