The monthly incomes from a random sample of workers in a factory are shown

Question

below.

Monthly Income
(In $1,000)
4.0
5.0
7.0
4.0
6.0
6.0
7.0
9.0

a. Compute the standard error of the mean (in dollars).
b. Compute the margin of error (in dollars) at 95% confidence.
c. Compute a 95% confidence interval for the mean of the population.
Assume the population has a normal distribution. Give your answer in dollars.

Answer 1

You will need to compute the mean and standard deviation. Once you have those values, you can compute the rest using formulas.

a) standard error of the mean = sd/√n
Note: sd = standard deviation; n = sample size

b) Margin of error = 1.96(sd/√n)
Note: 1.96 represents 95% using a z-table

c) CI95 = mean ± 1.96(sd/√n)

I'll let you take it from here.