Question

the monthly incomes for 12 randomly selected people, each with a bachelor's degree in economics are shown on the right.

assume the population is normally distributed.

4450.75 4596.58 4366.54

4455.91 4151.25 3727.05

4283.82 4527.79 4407.21

3946.06 4023.53 4221.05

a) find the sample mean

b) find the sample standard deviation

c) construct a 99% confidence interval for the population mean u (___,___)

Answer 1

For sample data   

Sample Mean is

Sample Standard deviation is

a) Sample mean is

b) Sample Standard deviation

c) The confidence interval is given by

For 99% confidence interval

So using the data we get