Random samples of size 49 are taken from an infinite population whose mean is 300 and standard deviation is 21.The mean and standard error of the sample mean,respectively,are:
A)300 and 21
B)300 and 3
C)300 and 0.43
D)None of these choices.

Question

Quizplus · Accepted Answer

The mean of the sample mean is equal to the population mean, which is given as 300. Hence, options A and C can be eliminated. 
The standard error of the sample mean can be calculated as: 
standard error = standard deviation / sqrt(sample size) 
= 21 / sqrt(49) 
= 3 
Therefore, the answer is B.

Random Samples of Size 49 Are Taken from an Infinite