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Count Frequency

When your data is pre-aggregated with counts, use a Count column as the frequency. Quantum XL expands the dataset by the count value, so a row with measurement 15.3 and frequency 18 is treated as eighteen observations of 15.3.

Goal

Create a box plot from pre-aggregated measurement data where each row represents a unique measurement value and how many times it was observed.

Sample Data

Press Copy for Excel, then paste the table into a blank worksheet.

Measurement	Frequency
10.2	3
12.5	7
14.0	12
15.3	18
16.1	15
17.8	10
19.4	6
21.0	4
23.7	2
28.5	1

There are only 10 rows, but the frequencies add up to 78 total observations. The most common measurement is 15.3 (observed 18 times), and the distribution tapers off toward the extremes. Quantum XL will expand the data so that each measurement is repeated by its frequency count.

Steps

1. Put the data in Excel

   Press Copy for Excel above the table, click cell A1 in a blank worksheet, and press Ctrl+V. The header row lands in row 1 and the 10 data rows in rows 2 through 11.

2. Launch the analysis

   From the Excel ribbon, select QXL Stat Tools → Analysis Tools → Box Plot.

3. Select your data

   Select cells A1:B11 (the header row plus all 10 data rows).

4. Configure the analysis

   In the Box Plot dialog:

   • Deselect "Frequency" under Data Columns (if auto-selected)
   • Check "Frequency" under Frequency Data (Optional)

   Click Finish to generate the chart.

Result

Quantum XL creates a box plot with one box for the Measurement column. The chart label shows "Measurement (N = 78)", reflecting the expanded dataset (the sum of all frequencies), not the 10 rows in the spreadsheet. The box plot statistics (median, quartiles, whiskers) are calculated on the full expanded dataset, giving an accurate picture of the distribution even though the source data was pre-aggregated.