I'm okay with solving regular normal distribution questions (where $X$ is a normal random variable with mean $\mu$ and standard deviation $\sigma$). However, we're currently dealing with samples within a larger population and I'm struggling to understand how the process of solving a question goes.
Here's an example:
The weight of a car is normally distributed with a mean of $2500$ and a standard deviation of $50$. Next, a random sample of $5$ cars is taken. What is the standard error of the sample mean?
I know that the standard error of the sample is:
$ \frac{\sigma^2}{n} $
but a question can't be this easy to answer can it? It's leading me to believe I'm missing a concept. If someone would be able to walk through the procedure of solving a question of this nature it would be greatly appreciated.