TamStat is a statistical package written in Dyalog APL. What distinguishes it from other statistical programs such as R, Minitab and Excel are its natural use of arrays, operators and namespaces.

Example: If the average student weighs 120 pounds with a standard deviation of 25, what is the probability that a randomly selected student will weigh over 150 lbs.?

**EXCEL: =1-NORM.DIST(150,120,25,TRUE)****R: pnorm(150,120,25,lower.tail=FALSE)****TamStat: 120 25 normal probability > 150**

# Why another Statistical Program?

Many students are confused by the sheer number of statistical functions. R has four functions for each statistical distribution, while Excel has six functions for the t-distribution alone. TamStat attempts to alleviate this problem by having only one function for each distribution. In TamStat there are four basic classes of functions: summary functions, distribution functions, relational functions and logical functions. What is unique about TamStat is the introduction of operators which combine functions in different ways to calculate probabilities, critical values and confidence intervals, perform various hypothesis tests, do simulations and conduct advanced operations such as regression, anova, goodness-of-fit tests and tests of independence.

TamStat is appropriate for use by both beginning and advanced students of statistics. There are three versions of TamStat: A standalone app with a user interface for students, a workspace for Dyalog APL programmers, and a web application similar to TryAPL.