Question

1. A simple random sample of size 15 is drawn from a normal population whose standard deviation is assumed to be 8. What's the margin of error if you're going to construct a 95% confidence interval for the population mean?

Answer 1

Answer:

± 4.05

Explanation:

Data provided in the question:

Random sample size = 15

Standard deviation = 8

Confidence level = 95%

Now,

Margin of error is given as:

Margin of error = ± [ ( z × s ) ÷ √n ]

Here,

From standard z table for 95% confidence level z = 1.96

Margin of error = ± [ ( 1.96 × 8 ) ÷ √15 ]

or

Margin of error = ± [ 15.68 ÷ 3.873 ]

or

Margin of error = ± 4.05