Statistics Tutorials

Introduction to Confidence Intervals

Understand the margin of error, the confidence level and how confidence intervals describe the variability of a samples.

The Standard Deviation

Variability is a fundamental concept in statistics. This tutorial covers the standard deviation and why measuring variability is so important.

Fundamentals of Statistics 1: Basic Concepts

If you know nothing about statistics, this is the place to start. The tutorial covers basic concepts such as the mean, standard deviation, populations and sample statistics.

Fundamentals of Statistics 2: The Normal Distribution

This tutorial continues where Fundamentals I left off. It covers the normal distribution in detail including how to find the probabilities of events using the normal curve.

Fundamentals of Statistics 3: Sampling

Sampling distributions, the standard error and applying the normal distribution to make predictions will become the foundation for almost everything you do in statistics.

Comparing Two Means: 2 Sample t-test

Is there a statistically significant difference between two groups? The 2-sample t-test is the most popular statistical test and this tutorial shows you in vivid animation how it works and how you can use it to compare two means.

Calculators

2 Sample t-test

Compares the means of two data-sets using the t-distribution.

1 Sample t-test

Compares the means of one data-set against a test mean using the t-distribution.

Percentiles from the t-Distribution

Calculates the percent of area under the student t distribution given a t-score and degrees of freedom.

Inverse t-Distribution

Calculates the critical value from the student t distribution given a proportion of area and degrees of freedom.

Standard Deviation

Computes the sample standard deviation and population standard deviation from a dataset.