Answer:
Step-by-step explanation:
We want to determine a 95% confidence interval for the mean total cholesterol level of all males.
Number of sample, n = 355
Mean, u = 185 mg
Standard deviation, s = 16
For a confidence level of 95%, the corresponding z value is 1.96. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
185 +/- 1.96 × 16/√355
= 185 +/- 1.96 × 0.849
= 185 +/- 1.66404
The lower end of the confidence interval is 185 - 1.66404 =183.336
The upper end of the confidence interval is 185 + 1.66404 = 186.66
Therefore, with 95% confidence interval, the mean total cholesterol level of all males is between 183.336 mg and 186.66 mg
