boxplot / outlier: how to reduce outliers(boundry change)?

Hey

We have this boxplot with our matrix we have attached to this post. the code is:

cst = x_weekday(:,:,2);
boxplot(cst');

the boxplot it givs is:

Question: The + signs is the outliers, but it looks like there is alot of those clumped together in 1 place. that is because it uses the default boundry of outlier that matlab provides. is it possible to change the outlier boundry so it has less outlier(+).

thanks

Answer 1

[the cyclist]

Yes, by setting the "whisker" option. Compare these two figures:

rng(1)

x = randn(10000,5);

figure
boxplot(x)

figure
boxplot(x,'whisker',2)

Answer 2

[awda]

hi thanks..but there is no real difference..when i put my code...any better options to change the boundry?

[the cyclist]

Did you run my example? It actually makes quite a large difference in the number of outliers.

I just set the whisker to length 2, but you can make the whisker much larger if you want, to eliminate more outliers.

Read

doc boxplot

for all kinds of details on how you can change these things.

[Also, it would have been better if you had placed your remarks as a comment under my answer, rather than as its own separate "answer".]

[awda]

ok thanks :), i will try asap, and return to you :)