%% Use Two Grouping Variables to Split Data
% Calculate mean blood pressures for groups of patients from measurements grouped by gender and status as a smoker.
% Load blood pressure readings, gender, and smoking data for patients from the data file patients.mat.

load patients
whos Systolic Diastolic Gender Smoker

%
% Specify groups using gender and smoking information about the patients. G contains integers from one to four because there are four possible combinations of values from Smoker and Gender.

G = findgroups(Smoker,Gender);
G(1:10)

%
% Calculate the mean blood pressure for each group.

meanSystolic = splitapply(@mean,Systolic,G);
meanDiastolic = splitapply(@mean,Diastolic,G);
mBP = [meanSystolic,meanDiastolic]

% Copyright 2015 The MathWorks, Inc.