Center and spread


Center-and-spread Little App: Household income (as a multiplier of the poverty level) versus whether the household owns or rents their home. Note the skew distribution for renters. Click here to launch.

The Center-and-spread Little App displays a jittered point plot of the response variable, which can be annotated with a variety of statistics often used to quantify “center” and “spread.”

  • Standard deviation “ruler” helps clarify that the sd is a distance rather than a value of the variable.
  • Compare the confidence interval on the mean to the summary interval of the response variable. This helps to dispell the misconception that the confidence interval contains most of the data.
  • Measuring stick to support reading values and differences off the graph.
  • Explore robustness by selecting new samples from the population.