Answer:
True.
Step-by-step explanation:
If we have for a sample of size n=25 a sample variance of 400, the standard error can be written as:

This way of calculating the standard error is the same used for estimating the standard deviation of the sample means for samples of size n=25.
<em>Answer,</em>
<em>21 * 50 = </em><em>1,050</em>
<em>Explanation Down Below,</em>
Multiply 4 on both sides.
x = 8 / 5
x = 1 3/5
Hope this helps!