A chi-square test calculates how far apart two sets of numbers are from each other. I.e., “observed” versus “expected.” This distance is translated into a … Read More

The value of t-statistic represents a distance, but it’s a distance in units called “standard errors.” It is also point on a curve whose shape … Read More

There’s a new landing page design you launch and see that it boosts conversion rate from five percent to seven percent. Huzzah! Your team cheers … Read More

You perform an A/B test on your landing page and find out that variant B has a higher conversion rate of 1.2 percentage points. Sweet! … Read More

It is a factory floor. There is a clipboard. Bottles roll along on a conveyor belt. Is it what the bottle say? It is fifty … Read More

So, now you have the after scores. And there are the before scores. But what do they mean? Are those two sets of number real … Read More

Imagine you are trying out a new way of teaching, splitting one half of the class up and teaching them one way while leaving the … Read More

Something feels different. Perhaps you suspect that your new manufacturing process is actualy faster. Or maybe the average test score in your class have changed … Read More

If you’ve taken most statistics classes, you’re familiar with determining p-values; not so much with the limits upon which their significance depend. Enter: the critical … Read More

Take as an example: A national poll say that a candidate is ahead by five percentage points, while the poll has a three percent margin … Read More