Answer:
The estimated standard error of the mean is 15
Step-by-step explanation:
The standard error a sample mean is given by the following formula:
[tex]SE = \frac{s}{\sqrt{n}}[/tex]
In which s is the standard deviation of the sample and n is the size of the sample.
In this problem, we have that:
[tex]s = 120, n = 64[/tex].
So
[tex]SE = \frac{120}{\sqrt{64}} = 15[/tex]
The estimated standard error of the mean is 15
