Example of a stacked bar chart of a function
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You are a quality engineer for a tire company and you need to quantify the various causes for tire repairs in the past year. You categorize and count all the reported instances of tire failure for the year. You suspect that the causes vary by quarter. Chart the number of each type of repair by quarter.

1    Open the worksheet TIRES.MTW.

2    Choose Graph > Bar Chart.

3    From Bars represent, choose A function of a variable.

4    Under One Y, choose Stack. Click OK.

5    From Function, choose Sum.

6    In Graph Variables, enter Repairs.

7    In Categorical variables for grouping (2-4, outermost first), enter Qtr CausesB.

8    Make sure that Stack values of last categorical variable is checked. Click OK. 

Interpreting the results

The third quarter has the most repairs, followed by the second quarter, first quarter, and fourth quarter. A disproportionate amount of punctures occurred in the third quarter. You may want to further investigate this phenomenon.