Home / Statistical Tools / Analysis Tools / Boxplot / Examples / GroupBy
GroupBy¶
Use GroupBy to create separate box plot charts for each group in your data, making it easy to compare distributions across shifts, departments, or locations.
Goal¶
Compare measurement distributions between Day and Night shifts to see whether one shift produces more variable results than the other.
Sample Data¶
Excel Protected View
When you open downloaded files, Excel displays a Protected View warning. You must click Enable Editing before you can use Quantum XL with the file.
Alternatively, you can copy the sample data from the table below and paste it directly into a new Excel workbook.
| Measurement | Shift |
|---|---|
| 25.3 | Day |
| 27.1 | Night |
| 24.8 | Day |
| 31.5 | Night |
| 26.0 | Day |
| 29.7 | Night |
| 25.5 | Day |
| 28.3 | Night |
| 24.2 | Day |
| 33.0 | Night |
Each row represents one measurement tagged with the shift when it was taken. Day shift has 5 observations and Night shift has 5 observations.
Steps¶
-
Launch the analysis
From the Excel ribbon, select QXL Stat Tools → Analysis Tools → Box Plot.
-
Select your data
Select cells A1:B11 (the header row plus all 10 data rows).
-
Configure the analysis
In the Box Plot dialog:
- Select the GroupBy radio button (instead of Excel)
- Data Columns: "Measurement" should be checked, "Shift" should be unchecked
- GroupBy: Move "Shift" to the GroupBy Order list
Click Finish to generate the charts.
How GroupBy Works
When you add a GroupBy column, Quantum XL creates a separate chart for every unique value in that column. In this example, the "Shift" column has two unique values — "Day" and "Night" — so we get two charts.
Result¶
Quantum XL creates two box plot charts, one for each shift:
Day Shift — Five measurements ranging from 24.2 to 26.0, with a relatively tight distribution.
Night Shift — Five measurements ranging from 27.1 to 33.0, with a wider spread and higher center.
The two charts make it easy to see that the Night shift produces higher and more variable measurements than the Day shift.
Common Vertical Axis
Enable All Charts Share Common Vertical Axis Scale in the Box Plot Options tab to make visual comparisons between charts easier. Without this option, each chart scales independently, which can make differences harder to spot.