Question

To estimate the average annual expenses of students on books and class materials a sample of size 36 is taken. The sample mean is $850 and the sample standard deviation is $54. A 99% confidence interval for the population mean is:_______.A) $823.72 to $876.28.
B) $832.36 to $867.64.
C) $826.82 to $873.18.
D) $825.48 to $874.52.

Answer 1

Answer:

C) $826.82 to $873.18.

Step-by-step explanation:

Sample mean (M) = $850

Standard deviation (s) = $54

sample size (n) = 36

Z for 99% confidence interval (Z) = 2.576

The confidence interval is determined by the following relationship:

$M \pm Z*\frac{s}{\sqrt{n}}$

Applying the given values, the lower (L) and upper (U) values are:

$850 \pm 2.576*\frac{54}{\sqrt{36}}\\L=\ 826.82\\U=\ 873.18$

The answer is C) $826.82 to $873.18.