Descriptive Statistics Exercise

Your Name ________________________________

These are explained on Tronchim's WEB page on Descriptive Statistics.   You can use the "Descriptive Statistics" tool on the "Tools" menu in Excel to do these if you wish.  However, on the exam you will have to do them with a hand calculator.  Remember to round your answers off correctly, give two digits after the decimal point.  Remember also that these results are dollars, so they should be reported with a dollar sign ($).  If you do not have Excel configured to do this, you need to put the results in the correct form for WEBCT, e.g, 55595 means $55595.00.

Note:  if you use a hand calculator, it is necessary to rescale the data to avoid getting a number that is too large for the calculator to handle when you square the differences in computing the standard deviation.   To do this, just move the decimal over three points to the less.  Thus the salaries become 85, 60, 40 and 9.  When you get your final result, you just move the decimal back three points to get the original scale.

The following are the salaries of officers in a police department:
       The chief makes $85,000 per year,
       Two sergeants make $60,000 per year,
       Six patrol persons make $40,000 each, and
       Two trainees make $9,000 per year.

3.    Compute the mean salary for the department?  This should be in dollars and typed in the following form ($99,999.99).  WEBCT will only accept it in that form.                                    .
 

4.    What is the median salary for the department?                                 .
 

5.     What is the range of the salaries in the department?  The range is the distance between the highest and the lowest.  E.g., if the highest was $40,000 and the lowest $10,000 then the range would be $30,000.00                        .
 

6.    What is the standard deviation of the salaries in the department?                                        .
                  (Tronchim also explains how to compute this, and gives an example.)