Question

Based upon extensive data from a national high school educational testing program, the standard deviation of national test scores for mathematics was found to be 120 points. If a sample of 225 students are given the test, what would be the standard error of the mean?

Answer 1

Answer:

8 is the standard error of mean.                                      

Step-by-step explanation:

We are given the following in the question:

Sample size, n = 225

Standard deviation = 120

We have to find the standard error of he mean.

Standard error is the ration of standard deviation to square root of sample size.

Formula:

$\dfrac{\sigma}{\sqrt{n}} = \dfrac{120}{\sqrt{225}} = 8$

Thus, 8 is the standard error of mean.