Here are the prices for 8 different MP3 players. Find the standard deviation.

$195 $358 $201 $276 $161 $301 $387 $128

The mean is 250.875.

Using this information, I can put the following into a calculator:

√ (((250.875-195) ² + (250.875-358) ² + (250.875-201) ² + (250.875-276) ²+

(250.875-161) ² + (250.875-301) ² + (250.875-387) ² + (250.875-128) ²) : 8)

Which equals:

87.9878

This is the standard deviation of the MP3 players.