I am not given the standard deviation in this problem. I understand that the following holds when the data is normally distributed:
Upper 95% bound $= (\bar{X} + (SE) \cdot 1.96)$
I have all of these values, but the only way I see to relate them to $n$ is through:
$SE = \frac{\sigma}{\sqrt{n}}$
but because I dont have the stdev, I don't understand how all of these pieces connect so that I can find $n$.