The table shows data on asthma-related visits. Is there evidence that these visits vary by quarter? Can you detect a trend? A powerful tool would be to run a multiple regression in Excel. If the function is already loaded, you will find it in Data > Data Analysis > Regression. If not, get help in adding the Analysis Tool Pak. To test for quarterly differences, create a variable called Q1 that equals 1 if the data are for the first quarter and 0 otherwise, a variable called Q2 that equals 1 if the data are for the second quarter and 0 otherwise, and a variable called Q4 that equals 1 if the data are for the fourth quarter and 0 otherwise. (Because you will accept the default, which is to have a constant term in your regression equation, do not include an indicator variable for quarter 3.) Also create a variable called Trend that increases by 1 each quarter.

Year	Q1	Q2	Q3	Q4
2001			1513	1060
2002	1431	1123	994	679
2003	1485	886	1256	975
2004	1256	1156	1163	1062
2005	1200	1072	1563	531
2006	1022	1169