Z star values table statistics excel

A Z-Score is a statistical value that tells you how many standard deviations a particular value happens to be from the mean of the entire data set. P formulas to calculate the mean and standard deviation of your data and then use those results to determine the Z-Score of each value. A Z-Score is a simple way of comparing values from two different data sets.

Z critical value excel formula

It is defined as the number of standard deviations away from the mean a data point lies. The general formula looks like this:. Here's an example to help clarify. Say you wanted to compare the test results of two Algebra students taught by different teachers. You could calculate the Z-Score of each student's score based on the average scores in each class and the standard deviation of the scores in each class.

It simply adds up all of the values in a cell range and divides that sum by the number of cells containing numerical values it ignores blank cells. The other statistical value we need is the 'standard deviation' and Excel has two different functions to calculate the standard deviation in slightly different ways. Previous versions of Excel only had the "STDEV" function, which calculates the standard deviation while treating the data as a 'sample' of a population.