Pooled variance

Pooled variance is a way to measure the amount of variability in a set of numbers. It combines the information of all the numbers to find one 'average' variance that explains how much the numbers change. To find the pooled variance, you take all the numbers and divide by their total number to get the average, then take the difference between each number and the average and square it. You then add all the squares together and divide by the total number minus one. This gives you the pooled variance.