Answer:
Step-by-step explanation:
We want to construct a 99% confidence interval for the population mean
Number of sample, n = 60
Mean, u = $150
Standard deviation, s = $36
For a confidence level of 99%, the corresponding z value is 2.58. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
150 ± 2.58 × 36/√60
= 150 ± 2.58 × 4.65
= 150 ± 11.997
The lower end of the confidence interval is 150 - 11.997 = 138.003
The upper end of the confidence interval is 150 + 11.997 =161.997
Therefore, with 99% confidence interval, the population mean is between $138.003 and $161.997
