Ok, so I messed up displaying the questions in a previous thread now. Here is the question straight from my worksheet.

For the data set s={x_1,x_2,...,x_n}

Show /sigma x^2= (\sum \frac{x_i^2}{N})-\mu x^2

Where /mu x= /frac{\sum x_i}{N}

All sums between i=1