Compare Screen

The Compare Screen is the third of five main charting views in QWXL 3. It is made up of three elements: the Control Chart, Histogram, and Statistics Box.

QWXL3 Compare Screen

Control Chart

The Compare Screen features a Control chart that allows you to compare two separate data sets within the same data population for one variable. Each separate data set can be sized using the tibs at the top of the chart. Limits are calculated for each data set and that portion of the chart is sized appropriately, while the limits for the overall data population remain in the background.

This view allows you to visually determine if there are different trending periods within a data population, helping you to identify possible changes in the process environment.

Dual Histogram

Histogram in QWXL3

The Histogram chart in the Compare Screen graphically displays the distribution of each of the two data sets as it relates to variance. This first set of data is represented in dark blue, the second in light blue. The Histogram also calculates a “t test” to determine if the Average of each data set is different, as well as an “F test” to determine if the variation of each data set is different. These results are displayed below the histogram.

Statistics Box

Statistics Box in QWXL3

The Compare Screen includes a Statistics box that shows over 100 standard statistical calculations for each data set. The two values are compared for each statistic and the difference is displayed, both as a real number and as a percentage. The number of displayed statistics can be set by the user. Additional information is available on the Statistics page.