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Qstat Desktop
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Dot Plot Maker

Group modest-sized data such as processing times into intervals and stack one dot per value. Individual data points stand out better than in a histogram.

1Data Table

Paste a table copied from Excel into a cell (Ctrl+V). Click a column header (A, B…) before pasting to use the first line as column names. Double-click a header to rename it, right-click to insert/delete rows and columns, and formulas such as =A1*2 work too.

2Dot Plot Options

Select one data column to plot:

How to make a dot plot

  1. Copy the numeric column to plot together with its header.
  2. Click the column header (A) in the data table and paste - the first line becomes the column name. You can also open a CSV or Excel file.
  3. Select one data column, and leave the interval width blank (automatic) or enter one.
  4. Press Draw and check the shape of the stacked dots and the automatic interpretation.

What is a dot plot?

A dot plot puts values on the horizontal axis and stacks as many dots as there are data points in each interval. Because each point is a dot rather than part of a bar, you can count the data directly, and with small samples it shows the distribution more honestly than a histogram.

Intervals

With the interval width blank, (max - min) / 20 is used. Each value goes into the interval number given by rounding 'value ÷ width', and the dots are stacked from the smallest value at the position interval number × width.

How to read a dot plot

  • Tall stacks show where the data concentrate. A dot sitting alone far away may be an outlier.
  • The automatic interpretation reports the number of outliers (IQR rule) and the skew judged from the skewness (toward larger values, smaller values, or symmetric).
  • The shape can change with the interval width - if it looks too fragmented, try a wider interval.

Frequently asked questions

How is it different from a histogram?

Same idea, but one dot per data point instead of bars. It is especially useful for small samples of 30 or fewer.

What appears when I hover?

The magnet cursor snaps to the nearest dot and shows its original value.

Why is there no y-axis scale?

Each dot is one data point, so you can simply count them (like the Qstat desktop program, no y-axis ticks are shown).

Is my data sent to a server?

No. Everything is processed inside your browser and nothing is transmitted or stored.

Other chart tools

Histogram MakerSee the distribution, a fitted normal curve and Pp/Ppk against spec limits at once.Stem-and-Leaf Plot MakerSplit values into stems and leaves to see the distribution while keeping the values readable.Violin Plot MakerCompare groups like a box plot while also showing the distribution shape as a curve.

Need process capability, control charts or DOE?

The Qstat desktop program offers about 250 analysis features: histograms and box plots plus process capability (Cp, Cpk), control charts, measurement system analysis (MSA), design of experiments (DOE), regression and machine learning.

Try Qstat free for 30 days