Question

When finding the standard deviation of a population, how do I know it's population? Will the question be direct or will the data look a certain way?

Answer 1

Standard Deviation is a measure of spread of a data distribution. It measures the typical distance between each data point and the mean.

Most of the times it is clearly mentioned in the question to find standard deviation of the population; however if the question is not direct, then it depends on the reason why you are calculating the standard deviation.  

In the case of sampling, you randomly select a set of data points for the purpose of estimating true value.

In the case of population, you are collecting 100% of the data.