# Welcome to Staz

(These demonstrations/illustrations will run only on Java-enabled browsers.)

### INTRODUCTION

 Binomial Demonstration Binomial Spinner Demonstration Alpha Illustration Complete Means Demonstration Power Illustration Central Limit Demonstration Correlation Demonstration Zentral Limit Demonstration Regression Demonstration Student's t Demonstration Anova1 Demonstration Variance Demonstration Anova2 Demonstration

## Introduction

This program has been designed as a supplement to your Introductory Statistics course.  It contains demonstrations and illustrations of important theoretical concepts, a couple of games, as well as detailed explanations of each demonstration or illustration.  We hope that using this program to augment what you learn in lectures and texts will increase your understanding of statistics.

If you are thinking of exploring elements of this program before you have reached the relevant section in your text and lectures, you may want to consider the following (which you may remember from Introductory Psychology):

The procedure is really quite simple.  First you arrange things into different groups depending on their makeup.  Of course, one pile may be sufficient depending on how much there is to do.  If you have to go somewhere else due to lack of facilities that is the next step, otherwise you are pretty well set.  It is important not to overdo any particular endeavor.  That is, it is better to do too few things at once than too many.  In the short run this may not seem important, but complications from doing too many can easily arise.  A mistake can be expensive as well.  The manipulation of the appropriate mechanisms should be self-explanatory, and we need not dwell on it here.  At first the whole procedure will seem complicated.  Soon, however, it will become just another facet of life.  It is difficult to foresee any end to this task in the immediate future, but then one never can tell. (Bransford & Johnson, 1972, p. 722.)

Bransford and Johnson (Contextual prerequisites for understanding.  Journal of Verbal Learning and Verbal Behavior, 11, 717-726) used this passage in their study of comprehension and recall.  Two groups of subjects heard the passage, and were asked to try to understand and remember it.  One group heard nothing but this passage; the second group heard first that the passage was on washing clothes.  Bransford and Johnson found that people in the second group were much better at understanding and remembering the passage than those in the first group.  The first group had no context in which to integrate the passage; the second group could readily integrate it into their knowledge of washing clothes.

What does this have to do with exploring the programs on the disk?   The context for understanding the demonstrations and illustrations in STAZ will be given by your text and lectures.   Our demonstrations and illustrations are not meant to stand alone.   If you find while exploring some of the demonstrations, illustrations, and Help files ahead of time that you comprehend little, don't worry or become anxious.   By the time you reach the relevant sections in your text and lectures, you'll be able to comprehend, and even enjoy, working with the demonstrations and illustrations!

#### Getting Started

STAZ is pretty user-friendly. You are presented with a menu of demonstrations and illustrations.  When you select the demonstration or illustration that you want to see (by clicking on the hypertext), you will link to a new page with four or five of the following items:

#### How Do I Do It?

gives step-by-step instructions for running the demonstration or illustration.

We strongly recommend that you consult 'How Do I Do It' before using any demonstration or illustration for the first time!

#### What Will I See?

describes the various elements of the demonstration or illustration that appear on your screen.

#### Purpose

describes the general aims of the demonstration or illustration.

#### What Can I Demonstrate (Illustrate)?

identifies what can be demonstrated (illustrated), and how to do it.

### Do It!

starts the demonstration or illustration.

In a number of demonstrations, you can consult the Teacher's PET.  The Teacher's PET is a Plain English Translation of what's happening in the demonstration.  The Teacher's PET explains certain statistical concepts in more detail, and as much as possible, without using statistical jargon.  (You will find however, that is often not possible to talk about statistical concepts without the use of some jargon.  Certain terms can't be avoided, nor should they be.  If you come across a term that you don't understand when consulting the Teacher's PET, you might want to use that as an indication that you need to review some of the concepts that you learned earlier in your course.)

#### A Rough Guide for using the Demonstrations and Illustrations

There is some variation in the topics that are included in Introductory Statistics courses, as well as some variation in the order in which the topics are presented.  There is also some variation in the names given to certain concepts in statistics. Below is a rough guide indicating when a particular demonstration or illustration will be relevant in the context of your course.

 When you are studying: Use: The Binomial Distribution / Random Sampling / Probability Binomial Demonstration / Binomial Spinner Demonstration The Central Limit Theorem / Sampling Distribution of the Mean / Distribution of the Sample Mean / Standard Error Complete Means Demonstration / Central Limit Demonstration Hypothesis testing with z-scores Zentral Limit Demonstration The t statistic Student's t Demonstration Distribution of the Sample Variance Sample Variance Demonstration Hypothesis testing / Type I error Alpha Illustration Hypothesis testing / Type II error / Power Power Illustration Correlation Correlation Demonstration Linear Regression / Regression / Least-squares prediction / Least -squared error Regression Demonstration 1-way Analysis of Variance Anova1 Demonstration 2-way Analysis of Variance Anova2 Demonstration

What Now?

If you want to quit in the middle of a demonstration, pushing [Esc] will get you out of the longer demonstrations.  Don't forget to put your Num Lock on!