Calculation of Measures of Dispersion, Skewness and Kurtosis with JASP

Just like the previous article, prepare your data with Excel or Notepad, save it as a CSV file.

Use the same steps to import the values into JASP. Once the values are imported, Click on “Descriptive” Button on top, add the required variable into “Variables” box.

Click on x and click that “>” arrow.

Go to the statistics tab below. Uncheck the values checked by default if needed.

Check under the “Dispersion” section to spot measures of dispersion like Range, Mean Absolute Deviation, Quartile Deviation (Also called Interquartile deviation, IQR), Standard Deviation and Variance.

To calculate quartiles, use the respective option under “Percentile Values”.

To calculate Skewness (measuring ‘symmetry’ of the data) and Kurtosis (measuring ‘steepness’ of data), use the respective options under ‘Distribution’ section.

The same can be achieved in Excel using the following formulas:

  1. STDEV.S (Standard Deviation)
  2. QUARTILE (Finding Quartiles)
  3. MAX and MIN (find Max and Min of the distribution and thereby calculate its range)
  4. Square STDEV.S result to get Variance
  5. SKEW for Skewness
  6. KURT for Kurtosis

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