Question

Noise levels at 5 construction sites were measured in decibels yielding the following data:

179,166,143,183,146,

Construct the 99% confidence interval for the mean noise level at such locations. Assume the population is approximately normal.

Step 2 of 4:

Calculate the sample standard deviation for the given sample data. Round your answer to one decimal place

Answer 1

Using Excel we get,

sample mean = 163.4

sample standard deviation = 18.4

Degrees of freedom = 5 - 1 = 4

t-critical value at significance level of 0.01 with 4 degrees of freedom is,

Excel Command : =TINV(0.01, 4) = 4.604

Margin of error (E) is,

The 99% confidence interval for the population mean is,

Therefore, the 99% confidence interval for the mean noise level at such locations is (125.51, 201.29).