Last steps

Compute the average

Sum	Average
0.0	NaN

Compute the Upper Control Limit

Simply compute the standard deviation and multiply by 3 and add to the average:

Compute the Lower Control Limit

Simply compute the standard deviation and multiply by 3 and subtract from the average:

For the lines, you have the data necessary to plot the chart.

Very last step

The percent of students getting a Free or Reduced Price Meal comes from the following sources:

	2015	2016	2017
Percent	8%	6%	7%
Data source	2015 data file	2016 data file	2017 data file