Is the Mean Finite?

The only way to standardize a variable is with finite mean and variance. The central limit theorem says that as the number of observations increases, increasing to infinity, the variable approaches a standard normal distribution. This means you can get probabilities very easily because they're all like z values,. And number two, it's symmetric. Oh, so if you make a test, or if you hypothesise on something that happens on the right, it also happens on the left. Now here is basically what you do in hypothesis testing, or mainly like standard, like standard hypothesis testing. What’s the probability that the standardized variable is less than some cut off value? So usually this is known as