Posts Tagged ‘ data analysis ’

Discover power laws by log-transforming data

December 5, 2016
By
Discover power laws by log-transforming data

A recent issue of Astronomy magazine mentioned Kepler's third law of planetary motion, which states "the square of a planet's orbital period is proportional to the cube of its average distance from the Sun" (Astronomy, Dec 2016, p. 17). The article included a graph (shown at the right) that shows

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Discover power laws by log-transforming data

Visualize the ages of US presidents

November 14, 2016
By
Visualize the ages of US presidents

Who was the oldest person elected president of the United States? How about the youngest? Who was the oldest when he left office? Let's look at some data. Wikipedia has a page that presents a table of the presidents of the US by age. It lists the dates for which

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Visualize the ages of US presidents

Sometimes you need to reverse the data before you fit a distribution

November 2, 2016
By
Sometimes you need to reverse the data before you fit a distribution

Occasionally on a discussion forum, a statistical programmer will ask a question like the following: I am trying to fit a parametric distribution to my data. The sample has a long tail, so I have tried the lognormal, Weibull, and gamma distributions, but nothing seems to fit. Please help!! In

The post Read more »

Tags: ,
Posted in SAS | Comments Off on Sometimes you need to reverse the data before you fit a distribution

Counting observations for which two events occur

October 31, 2016
By
Counting observations for which two events occur

Every year near Halloween I write an article in which I demonstrate a simple programming trick that is a real treat to use. This year's trick (which features the CMISS function and the crossproducts matrix in SAS/IML) enables you to count the number of observations that are missing for pairs

The post Read more »

Tags: , , ,
Posted in SAS | Comments Off on Counting observations for which two events occur

Loess regression in SAS/IML

October 19, 2016
By
Loess regression in SAS/IML

A previous post discusses how the loess regression algorithm is implemented in SAS. The LOESS procedure in SAS/STAT software provides the data analyst with options to control the loess algorithm and fit nonparametric smoothing curves through points in a scatter plot. Although PROC LOESS satisfies 99.99% of SAS users who

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Loess regression in SAS/IML

What is loess regression?

October 17, 2016
By
What is loess regression?

Loess regression is a nonparametric technique that uses local weighted regression to fit a smooth curve through points in a scatter plot. Loess curves are can reveal trends and cycles in data that might be difficult to model with a parametric curve. Loess regression is one of several algorithms in

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on What is loess regression?

The empty-space distance plot

October 12, 2016
By
The empty-space distance plot

How far away is the nearest hospital? How far is the nearest restaurant? The nearest gas station? These are commonly asked questions whose answers depend on the location of the person asking the question. Recently I showed an algorithm that enables you to find the distance between a set of

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on The empty-space distance plot

Visualize a weighted regression

October 5, 2016
By
Visualize a weighted regression

What is weighted regression? How does it differ from ordinary (unweighted) regression? This article describes how to compute and score weighted regression models. Visualize a weighted regression Technically, an "unweighted" regression should be called an "equally weighted " regression since each ordinary least squares (OLS) regression weights each observation equally.

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Visualize a weighted regression

Welcome!

SAS-X.com offers news and tutorials about the various SAS® software packages, contributed by bloggers. You are welcome to subscribe to e-mail updates, or add your SAS-blog to the site.

Sponsors





Dear readers, proc-x is looking for sponsors who would be willing to support the site in exchange for banner ads in the right sidebar of the site. If you are interested, please e-mail me at: tal.galili@gmail.com
SAS and all other SAS Institute Inc. product or service names are registered trademarks or trademarks of SAS Institute Inc. in the USA and other countries. ® indicates USA registration.