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    %% Use Western Electric 2 Rule
%% Load the sample data

% Copyright 2015 The MathWorks, Inc.

load parts;
%% XBar Chart with WE2 Rule
% Construct the Xbar control chart using the Western Electric 2 rule (2
% of 3 points at least 2 standard errors above the center line) to mark the
% out of control measurements.
st = controlchart(runout,'rules','we2');
%% Plot 2 Standard Errors Line
% For a better understanding of the Western Electric 2 rule, calculate and
% plot the 2 standard errors line on the chart.
x = st.mean;
cl = st.mu;
se = st.sigma./sqrt(st.n);
hold on
plot(cl+2*se,'m')
%% Identify Out of Control Points
% Identify the measurements that violate the control rule.
R = controlrules('we2',x,cl,se);
I = find(R)