Probably Random - Statistics for people who use numbers, not degrees
Statistics for people who use numbers, not degrees
The Definition of Regression to the Mean
Regression to the mean is the tendency for an unusually high or low measurement to be followed by one closer to the average, simply because the two...
Desmond Achebe • 6 min readOne-Tailed vs Two-Tailed Tests Explained
Use a two-tailed test unless, before any data arrives, you can say that a result in the opposite direction would lead to exactly the same decision as no...
Sofia Bianchi • 7 min readWhat Is P-Hacking
P-hacking is running several analyses on the same data until one of them comes out statistically significant, usually p < .05, and then reporting that one...
Desmond Achebe • 6 min readWhy a Bigger Sample Shrinks Your P-Value
Why does the same small lift look like noise in a small test and a sure thing in a big one? Because a p-value depends on two things, not one. It reflects...
Meera Krishnan • 5 min readWhat Counts as a Good P-Value
There is no single good p-value. What counts as "good enough" depends on your field and on what a false alarm would cost you. The conventions run from 0.10...
Meera Krishnan • 6 min readP-Value vs Confidence Interval
If you have both a p-value and a confidence interval for the same result, read the interval first. The two come from the same arithmetic, so a 95%...
Sofia Bianchi • 7 min readWhy 0.05 Is the Standard P-Value Cutoff
Why is the p-value cutoff 0.05? Ronald Fisher, a British statistician, called it convenient in a 1925 textbook, and nearly everyone followed him. It is a...
Sofia Bianchi • 5 min readHow to Calculate a P-Value by Hand
When you finish, you will have a two-tailed p-value for a one-sample t-test, built from four numbers: the sample mean, the sample standard deviation, the...
Meera Krishnan • 5 min read