Statistics, Probability, and Survey Sampling
The goal of this web site is to help you solve common statistical problems -
quickly, easily, and accurately - without having to ask anyone for help.
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Free statistics tutorials
cover the central ideas of basic statistics: probability,
distributions, sampling theory, estimation, hypothesis testing,
and survey sampling -- all explained in plain English.
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Analytical tools
eliminate computational drudgery. Everything is online
and easy to use. Frequently-asked questions and sample exercises
steer you clear of potential problems.
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Online statistics glossary
takes the mystery out of statistical jargon. To access the
glossary, simply click the Help link at the top of any Stat
Trek web page.
A few of Stat Trek's training aids and analytical tools are
described below.
To see the complete list of products and services,
click here.
Are you baffled by binomials, puzzled by proportions, dazed by
distributions, or just plain stymied by statistics? Stat Trek's
on-line statistics tutorials can help. One tutorial covers
statistics, probability, and survey sampling. The other
tutorial focuses exclusively on topics covered by the Advanced
Placement (AP*) Statistics examination. Both tutorials are set
up to get you productive as quickly and painlessly as
possible. Topics are introduced in short, easy-to-understand modules.
And, best of all, the tutorials are free.
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Learn more
Retrieve information quickly and easily from standard statistical tables.
Count combinations and permutations.
Compute probabilities and confidence intervals.
Whether you need a z-score, a t-score, a probability, a cumulative probability,
a list of random numbers, or other statistical information, Stat Trek's on-line
statistical tools will make the task quick and easy. >
Learn more
What sample size do I need? Will it provide the precision I require? Which
sampling method is best? How should I allocate sample to strata or to clusters?
Would a different design be cheaper or offer more precision? If these questions
sound familiar, then you need the Sample Planning Wizard. This on-line tool
allows you to easily compare different sampling methods and different sample
allocation plans to develop the most cost-effective survey sample design for
your study. >
Learn more
Each year, the College Board administers a standardized test called the Advanced
Placement Statistics Examination. The exam, which is open to everyone, assesses
proficiency in introductory statistics. Students who score well earn credit for
college-level courses. To pass the test, you need a good study guide, the right
calculator, and a willingness to study hard. Stat Trek can help you identify
the best study guide and calculator, so all you have to do is study.
> Learn more
Don't be without Stat Trek's flagship email newsletter - an easy-to-read source
of proven analytical strategies and tips that you can put to use with
confidence. Find the right techniques for valid, effective analysis. Identify
strengths and weaknesses of your research. Conduct cost-effective research.
Send no money - We're too busy to bill you. >
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We wish to express our appreciation to those who assisted in the development of
this web site. We are particularly grateful to the following folks.
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Many thanks to Peter J. Acklam, who wrote the algorithm for
the Normal distribution. He has generously shared that algorithm, and you can
access it at:
http://home.online.no/~pjacklam/notes/invnorm.
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We are also grateful to Geoffrey C. Barnes, Ph.D, who wrote a
helpful
VB.Net implementation of the Acklam algorithm.
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A big tip of the hat to Justus Randolph for discovering
and helping to correct an annoying bug in the Stat Trek program.
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And we are indebted to Ian Smith for alerting us to
a problem with the chi square calculator and for his practical
suggestions to fix the problem.
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