The Z-score allows us to express data in a way that provides more insight into each data point’s relationship to the overall distribution. The formula to compute a Z-score for a data point given that we know the value of the population mean μ \mu and standard deviation σ \sigma is: Z(x)= x − μ σ.
Step 2: Calculate The Mean. Since we will use the mean to determine the z score for our data set we need to calculate the mean. Mean means mathematical average in a group of data. Mathematically it means adding up all the numbers and divide them to 10 but in excel we use a simple formula for calculating quickly. A two proportion z-test is used to test for a difference between two population proportions. This tutorial explains the following: The motivation for performing a two proportion z-test. The formula to perform a two proportion z-test. An example of how to perform a two proportion z-test. Two Proportion Z-Test: Motivation Now, we have the Mean and SD. we can calculate the z-score manually in Excel. Step #3: Calculate the Z-Score in Excel. To calculate the z-score: Go to the FORMULAS tab. Under the Functions Library, click on More Functions; From the drop-down list, click on the Statistical Function category. From the list of functions, click on the STANDARDIZE Using Excel to Calculate a Z-Score for Statistical Analysis. The Z-score is calculated by subtracting the mean, or average, value from the data point and dividing the result by the standard deviation. ELzBK6d.