Question

A random sample is made of 256 middle managers concerning their annual incomes. The sample mean is computed to be $35,420. If the population standard deviation is $2,050. What is the standard error of the mean?
a. $128.125
b. $138.36
c. $2.050
d. $8.01

Answer 1

Answer: a. $128.125

Step-by-step explanation:

The standard error of the mean is given by :

$SE=\dfrac{\sigma}{\sqrt{n}}$ , where $\sigma$ = population standard deviation , n= sample size.

Given: $\sigma=\ 2,050$

n= 256

Then, the standard error of the mean:-

$SE=\dfrac{2050}{\sqrt{256}}\\\\=\dfrac{2050}{16}=\ 128.125$

Hence, option a. is correct.