I worked this out and are pretty sure I did it totally wrong.

Please help with business analysis homework. I worked this out and are pretty sure I did it totally wrong. Please show step by step

A small IT consulting firm has the following salaries (in thousands of dollars):

24,  30,  56,  47,  40

Compute the standard deviation of the salaries to two decimal places. Take all calculations toward the answer to at least three decimal places.