Understanding the results of your experiments can be a complicated affair. Luckily, there are a few simple methods to make sense of all the data your experiments accumulate and give you confidence in your findings.
In your experiments, you attempt to hold all variables constant except the thing you want to investigate. The reality, of course, is that many variables are not constant. You’re comparing similar groups, but those groups themselves will have differences that introduce noise. That’s where statistical significance comes in (Figure 7.1).