SAS Visual Analytics terms

Tools like SAS Visual Analytics and similar use terms like outlier and maximum and I wasn’t sure of the difference.

Today, I was looking at Box plots and while I could see the difference between an outlier and a maximum, I didn’t really know how each is calculated. Here goes….

SAS box plot

Source: (November 2014)

While mean, medium and percentile are fairly clear, I’m not sure how the Maximum and outlier are calculated.

SAS defines the maximum and outlier as:

Outlier: an observation outside the lower and upper fences. The fences are located at a distance 1.5 times the Interquartile Range (IQR = Q3 – Q1) above and below the box
Max: maximum data value less than or equal to the upper fence.

IQR (inter quartile range) = Q3 – Q1
Q1 – 1st quartile (25th percentile). The data must contain a nonmissing value for this quartile.
Q3 – 3rd quartile (75th percentile). The data must contain a nonmissing value for this quartile.

A Course in Data Analytics

I’m doing a part-time course in Data Analytics at the University of Brighton. Seems like a good excuse to post some stuff here and see if my site gets a new lease of life.

I’ll probably post things on here that I need to know.

Plotting data with d3.js and json – Brighton PHP October 2013

This is an example of a plot of the GA (google analytics) data stored in Json format. The data is plotted using d3.js. Have a look at the gallery. I do not think I have done d3js justice with my line charts.

PHP and Fast Fourier Transform – Brighton PHP October 2013

Using data from google analytics (GA) (see other posts) a Fast Fourier Transform is performed on the time series data. The absolute value is saved for plotting using d3.js

Fourier Transforms and Time Series Data

I’m doing a talk at Big Data Brighton on April 25th. I will add the slides after but for now I’ll put up the matlab m file scripts. All at:

Slides for Time Series Data and FFT

This shows a single sinusoid and Fourier Transform
This is the example which takes several sinusoids, sums them and shows their Fourier Transforms

This is the filtering example