In: Statistics and Probability
4. In a sample of 10 people in Japan average life expectancy is 85 years with a sample standard deviation of 3 years. In a sample of 8 people in South Korea, the corresponding numbers are 82 years and 2 years.
(a) Find a 95% confidence interval for the population average difference in life expectancy.
(b) Suppose you wish to test the null that the two population life expectancy values are equal against the alternative that they are different. Find a range in which the P-value must fall.