Quartile & Percentile Calculation

Demonstrates a method for computing percentiles and other basic statistics.

Description

Included in the first line of the script is a sample data set. The script will compute basic statistics on this data set:

mean
1-sigma (standard deviation)
median
first quartile (25th percentile)
second quartile (50th percentile)
third quartile (75th percentile)
kth percentile
IQR
SID

• Acknowledgements: This submission has inspired the following:; medoultierfilt, Box Plot with Whiskers Plotted at Fixed Percentiles
• MATLAB release: MATLAB 7 (R14)

[Anthony Nigara]

Very helpful, I'm surprised that this isn't an included Matlab function!?

[J Choi]

must-have function for any statistical data process

[Nikhil Padhye]

Very useful indeed, but watch for a small error in the Q3 outlier calculation: you will need to replace Q(1)+3*IQR by Q(3)+3*IQR.

[Jimmy Yi]

Very helpful and neat!

[Gabriela Molina]

 

[Max Feltham]

clear and easy to use

[Hossein Kazemi]

Why does the file returns an error when x=randn(100,1)? There is no error if the length is different from 100!

[Ed Cruz]

 

[alex christ]

I thinks its really great but when i play with x array and i use a negative value it detects an outlier but doesnt say which one! If though use a positive value it detects the outlier plus says which value is the outlier!
Why is the negative value not recognized?

[alex christ]

If you remove the ; from line 39 at the end of outliersQ1 = y(iy) then even if you use a negative value you will see it detected n pointed out! :)
Great File n Should Be used as Build In for sure!

[Jeff Morin]

 

[Rainer Glas]

 

[Tony Fisher]

Well done: simple but to the point. Thank you (I use this in software that I give to users who don't have the MatLab Statistics tbx)
Best wishes Tony Fisher

[mathworks2011]

excellent

[Ela Fire]

Excellent work ! Matlab should implement in this in future