One number stands out from survey results. You see fifty-four percent approve. Maybe you’re confident now that you know. But here’s where it’s dangerous: what … Read More

Take a number. It is something you got out of a textbook problem or based off of a spreadsheet. Until you turn it into a … Read More

It is the scale. That’s where you begin. There is a number. Maybe it’s low. Maybe it’s high. So you check growth charts. Are your … Read More

This page contains a calculator that computes probabilities using standard normal curve. We use this as a reference curve because any bell-shaped distribution with mean … Read More

Most quality- and risk-related decisions is driven by the quiet engine of the normal distribution. Your commuting time follow a normal distribution. Your test scores … Read More

This page’s standard deviation of a population calculator is a measure of just how closely (or loosely) all members of a set of number cluster … Read More

Or maybe it’s a list of numbers… Your daily sales figure at your store, or your exam scores from your last class. Averages are great; … Read More

A z-score is a standardized measure of a data point. It represent how many standard deviations a particular value is away from mean. By doing … Read More

Imagine that you’re faced with a machine with 10 binary switches. You want to know the probability that if you flip every switch, you’ll get … Read More

You’ve probably heard people say “correlation doesn’t imply causation.” That’s true, and it’s a useful phrase taught in stats classes, but it don’t tell us … Read More