Please help me with this! I have no idea where to start. Please EXPLAIN how you got the answers so I can complete the remaining questions that are similar! Thank you!

The annual income of five vice-presidents of TRW Inc. are: $125,000, $128,000, $122,000, $133,000, and $142,000.  Consider that is the entire population and compute:

a.     Range,

b.    The arithmetic mean income and the median income,

c.     What is the population variance? The Standard Deviation {STDEV}?

d.    Compute and compare the sample variance with the population variance and discuss the differences.