Question

Random samples of size 81 are taken from a process (an infinite population) whose mean and standard deviation are 200 and 18, respectively. The distribution of the population is unknown. The mean and the standard error of the distribution of sample means are
A. 200 and 18
B. 81 and 18
C. 9 and 2
D. 200 and 2

Answer 1

Answer:

D. 200 and 2

Step-by-step explanation:

The mean of a sample taken from an infinite population can be approximated as the mean of the population, therefore, the mean of the sample is M = 200.

The standard deviation of a sample is determined as the population standard deviation divided by the square root of the sample size. The sample standard deviation is:

$s = \frac{18}{\sqrt{81}}=2$

The answer is D. 200 and 2