Deriving Statistical quantites from other quantities

Question

Studying for a statistics exam and I am stumped on the following:

For a set of sample data, the following values were found. Fill in missing values

Variable: X N: ? Mean: ? SE Mean: 2.05 StDev = 10.25 Variance ? Sum: 3761.70 Sum of Squares: ?

What's really throwing me off is the lack of N!

I know the SE mean is mean/sqrt(n)

But I have neither.

Variance is stDev^2. So that is simple enough.

But what of these other values?!

Answer 1

From the SE of the mean and standard deviation you can find $N$. For $\frac{10.25}{\sqrt{N}}=2.05$. It follows that $N=25$.

Note that the standard error is not the mean divided by $\sqrt{N}$.