The average age of a sample of 17 South African women who attend yoga classes was found to be 31 years, with a standard deviation of 3.5 years. Construct a 90% confidence interval for the true average...

The average age of a sample of 17 South African women who attend yoga classes was found to be 31 years, with a standard deviation of 3.5 years. Construct a 90% confidence interval for the true average age of all South African women who attend yoga classes.