In: Statistics and Probability
An economist wants to estimate the mean per capita income (in thousands of dollars). Suppose that the mean income is found to be $23.4 $23.4 for a random sample of 976 976 people. Assume the population standard deviation is known to be $10 $10. Construct the 95% 95% confidence interval for the mean per capita income in thousands of dollars.
Round your answers to one decimal place.
Answer:
Given that,
= 23.4
= 10
n =976
At 95% confidence level the z is ,
= 1 - 95% = 1 - 0.95= 0.05
/ 2 = 0.05/ 2 = 0.025
Z/2 = Z0.025= 1.96
Margin of error = E = Z/2* ( /n)
=1.96 * (10 / 976)
= 0.6274
=0.6
At 95% confidence interval estimate of the population mean is,
- E < < + E
23.4 - 0.6 < < 23.4+ 0.6
22.8< < 24.0
(22.8, 24.0)