Question

does the confidence interval indicate theres a significant difference in mean life expectancy between males and females? why? how? if there is a difference, what is it? be specific.

interval answer : lower bound -7.76 and upper bound: -2.64

Answer 1

Assume alpha = 0.05 (or any other)

The confidence interval of mean life expectancy between male and females is: (-7.76, -2.64)

The above CI means that if we use the same sampling method to computed the estimate of the sample, 95% (if alpha = 0.05) of the times the estimate will fall between this interval. Hence, as the CI is always negative and it does not contain 0, this means that the mean life expectancy of males is lesser than that of females and the difference could lie between the above interval. The above confidence interval contains the true difference of the population and we are 95% certain about it.