Question

a simple random sample is drawn from a normally distributed population, and when making a statistical inference about the population mean, the margin of error is found to be 5.9 at a 95% level of confidence. if the mean of the sample is 18.7, what is the 95% confidence interval for the population mean?
○ 18.7 ± 5.9
○ 18.7 ± 9.7
○ 18.7 ± 11.6
○ 18.7 ± 15.2

Explanation:

Step1: Recall confidence interval formula

The formula for a confidence interval for the population mean is $\text{Sample Mean} \pm \text{Margin of Error}$.

Step2: Identify given values

The sample mean is $18.7$ and the margin of error is $5.9$.

Step3: Apply the formula

Substitute the values into the formula: $18.7 \pm 5.9$.

Answer:

A. $18.7 \pm 5.9$