Covariate

A covariate is like an addition to a math problem that helps you get a more accurate answer. For example, let's say you want to figure out how many candies you can buy with $10. The price of each candy is not the same every time, so you need to know this information to make sure you get the right answer. This extra information, the price of each candy, is the covariate which helps you find the true answer.

Similarly, when scientists study things, they also use covariates to get more accurate results. For example, if they want to know if eating fruits and vegetables helps people live longer, they may also want to know if the people who eat more fruits and vegetables also exercise more or if they have a healthy weight. These extra facts are covariates. Scientists use them to make sure they know what other things are going on that might also be affecting a person's health. Like adding the price of each candy to the math problem, these extra facts help scientists get a better answer.