Box plots and distribution characteristics

Statistical Techniques in Tableau

Maarten Van den Broeck

Content Developer at DataCamp

Box plots

Visualize the distribution of a single, continuous variable

 

A plot of all data points on one line.

Statistical Techniques in Tableau

Box plots

Visualize the distribution of a single, continuous variable

 

The same plot, now with a median reference line.

Statistical Techniques in Tableau

Box plots

Visualize the distribution of a single, continuous variable

 

The same plot again, now with lower and upper quartile.

  • Distance between lower quartile and upper quartile is the interquartile range (IQR)
Statistical Techniques in Tableau

Box plots

Visualize the distribution of a single, continuous variable

 

Finally, the same plot now as a box plot.

  • Distance between lower quartile and upper quartile is the interquartile range (IQR)
  • Whiskers: length of 1.5 x IQR
  • Outlier: extreme value outside whiskers
Statistical Techniques in Tableau

When to use a box plot

Mulitple box plots allow for comparison between categories.

Statistical Techniques in Tableau

When to use a box plot

  • Compare distributions among multiple categories
  • Spot trends and differences between categories
Statistical Techniques in Tableau

What about the mean?

  • Average = arithmetic mean
  • $\frac{a_1+a_2+a_3+...+a_n}{n}$
  • Average and mean are often used interchangeably

 

The box plot from before, now with reference average line.

Statistical Techniques in Tableau

Skewness

Histograms and box plots displaying left-skewed, symmetric, and right-skewed distributions.

Statistical Techniques in Tableau

Skewness

Histograms and box plots displaying left-skewed, symmetric, and right-skewed distributions.

Statistical Techniques in Tableau

Skewness

Histograms and box plots displaying left-skewed, symmetric, and right-skewed distributions.

Statistical Techniques in Tableau

Skewness

Histograms and box plots displaying left-skewed, symmetric, and right-skewed distributions.

Statistical Techniques in Tableau

Excess kurtosis

Histograms and box plots displaying leptokurtic, mesokurtic, and platykurtic distributions.

Statistical Techniques in Tableau

Let's practice!

Statistical Techniques in Tableau

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