Posts Tagged ‘ data analysis ’

Two ways to compute maximum likelihood estimates in SAS

June 14, 2017
By
Two ways to compute maximum likelihood estimates in SAS

In a previous article, I showed two ways to define a log-likelihood function in SAS. This article shows two ways to compute maximum likelihood estimates (MLEs) in SAS: the nonlinear optimization subroutines in SAS/IML and the NLMIXED procedure in SAS/STAT. To illustrate these methods, I will use the same data

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Two ways to compute maximum likelihood estimates in SAS

Two simple ways to construct a log-likelihood function in SAS

June 12, 2017
By
Two simple ways to construct a log-likelihood function in SAS

Maximum likelihood estimation (MLE) is a powerful statistical technique that uses optimization techniques to fit parametric models. The technique finds the parameters that are "most likely" to have produced the observed data. SAS provides many tools for nonlinear optimization, so often the hardest part of maximum likelihood is writing down

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Two simple ways to construct a log-likelihood function in SAS

Runs in coin tosses; patterns in random seating

June 5, 2017
By
Runs in coin tosses; patterns in random seating

If you toss a coin 28 times, you would not be surprised to see three heads in a row, such as ...THHHTH.... But what about eight heads in a row? Would a sequence such as THHHHHHHHTH... be a rare event? This question popped into my head last weekend as I

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Runs in coin tosses; patterns in random seating

Sample quantiles: A comparison of 9 definitions

May 24, 2017
By
Sample quantiles: A comparison of 9 definitions

According to Hyndman and Fan ("Sample Quantiles in Statistical Packages," TAS, 1996), there are nine definitions of sample quantiles that commonly appear in statistical software packages. Hyndman and Fan identify three definitions that are based on rounding and six methods that are based on linear interpolation. This blog post shows

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Sample quantiles: A comparison of 9 definitions

Quantile definitions in SAS

May 22, 2017
By
Quantile definitions in SAS

In last week's article about the Flint water crisis, I computed the 90th percentile of a small data set. Although I didn't mention it, the value that I reported is different from the the 90th percentile that is reported in Significance magazine. That is not unusual. The data only had

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Quantile definitions in SAS

Quantiles and the Flint water crisis

May 17, 2017
By
Quantiles and the Flint water crisis

The April 2017 issue of Significance magazine features a cover story by Robert Langkjaer-Bain about the Flint (Michigan) water crisis. For those who don't know, the Flint water crisis started in 2014 when the impoverished city began using the Flint River as a source of city water. The water was

The post Read more »

Tags: ,
Posted in SAS | Comments Off on Quantiles and the Flint water crisis

Timeline of living US presidents

May 8, 2017
By
Timeline of living US presidents

Quick! What is the next term in the numerical sequence 1, 2, 1, 2, 3, 4, 5, 4, 3, 4, ...? If you said '3', then you must be an American history expert, because that sequence represents the number of living US presidents beginning with Washington's inauguration on 30APR1789 and

The post Read more »

Tags: ,
Posted in SAS | Comments Off on Timeline of living US presidents

Perceptions of probability

May 3, 2017
By
Perceptions of probability

If a financial analyst says it is "likely" that a company will be profitable next year, what probability would you ascribe to that statement? If an intelligence report claims that there is "little chance" of a terrorist attack against an embassy, should the ambassador interpret this as a one-in-a-hundred chance,

The post Read more »

Tags: , ,
Posted in SAS | Comments Off on Perceptions of probability

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.