Everything You Always Wanted to Know About Confidence Intervals (But Were Afraid to Ask) in 2 Minutes!

**Confidence intervals** might be a frightening topic for somebody who is not stats-savvy. Thus, we’ll start with something as simple as plums.

Let’s say we want to figure out the typical weight of a plum. For simplicity, let’s assume that we know the standard deviation of all plums’ weights:* σ=4 (grams)*. We’ll also assume that plum weights follow a *normal distribution*.

It is impossible to measure a weight of every single plum to calculate the true mean of plum weights (a.k.a. population mean). Thus, we’ll take 100 samples with 200 plums in each sample. We can visualize it as follows: