Confused by statistics? Know the formulas, but not how they all connect?

Learn a semester's worth of intro to stats in four videos.

By the end, you’ll understand the normal distribution, Z-scores, the Central Limit Theorem and how it animates hypothesis testing, and why confidence intervals are so useful. But more importantly, you’ll know how it all connects, so that statistics makes sense -- on test day and beyond.

So catch up, get ahead, or just get more out of stat class. Transcriptions are under the videos if you want to read more carefully, where you can click on the section headers to jump to any spot!

In this video, we explain:

- What the parameters variance, mean, and standard deviation are, exactly.
- How we use a sample to estimate the parameters of a population.
- How variance in a population can create variance (“error”) in sample means.

In this video, we explain:

- The normal and standard normal distributions.
- The Empirical Rule.
- Z scores.

In this video, we explain:

- The Central Limit Theorem, demonstrated with a coin flip experiment.
- How widely a sample mean is expected to vary, given the variance of a population and the sample size n.

In this video, we explain:

- How to set up hypotheses (Ho and Ha), the threshold of rejection (alpha), and tails for a parametric hypothesis test.
- When to use a Z vs. T test, and why.
- How to “reject Ho” and conclude a test.
- How confidence intervals work.

Below are the help content pages for each topic covered by statmagic's calculators. Each page gives a quick, high-yield discussion of the main ideas and formulas, a memorable example problem, and lastly, instructions on how to solve a problem using statmagic.

STATMAGIC copyright 2018 David Johnson & Dan Chenoweth.