User`s guide

excludedata

4-99

Remarks You can combine data exclusion methods using logical operators. For example,

to combine methods using the | (OR) operator

outliers = excludedata(xdata,ydata,'indices',[3 5]);

outliers = outliers|excludedata(xdata,ydata,'box',[1 10 0 90]);

In some cases, you might want to use the ~ (NOT) operator to specify a box that

contains all the data to exclude.

outliers = ~excludedata(xdata,ydata,'box',[1 10 0 90]);

Example Generate random data in the interval [0, 15], create a sine wave with noise, and

add two outliers with the value 2.

rand('state',0);

x = 15*rand(150,1);

y = sin(x) + (rand(size(x))-0.5)*0.5;

y(ceil(length(x)*rand(2,1))) = 2;

Identify outliers that are outside the interval [-1.5, 1.5] using the range

method.

outliers = excludedata(x,y,'range',[-1.5 1.5]);

Identify the same outliers using the indices method.

ind = find((y>1.5)|(y<-1.5));

outliers = excludedata(x,y,'indices',ind);

You can pass outliers to the fit function to exclude the specified data points

from a fit.

ftype = fittype('a*sin(b*x)');

fresult = fit(x,y,ftype,'startpoint',[1 1],'exclude',outliers);