Life expectancy in the US varies depending on where anindividual lives, reflecting social and health inequality byregion. You are interested in comparing mean life expectancies incounties in California, specifically San Mateo County and SanFrancisco County. Given the data below, answer the followingquestions.
| Mean life expectancy at birth for males in2014 | Sample standard deviation | Sample size (n) |
| San Mateo County | 81.13 years | 8.25 | 101 |
| SF County | 79.34 years | 9.47 | 105 |
1. Calculate the standard error of the mean difference in malelife expectancy between the 2 counties, assumingnonequal variance.
2. Calculate a 99% confidence interval for the meandifference in male life expectancy between the two counties. Usethe conservative approximation for degrees of freedom.
3.Based on your confidence interval, would you expect the meandifference in male life expectancy to be statistically significantat the α=.01 level? EXPLAIN
