Z score of mean
From OPOSSEM
When first introducing students to the concept of z scores in the context of progressively teaching increasingly complex difference of means tests, I use the standard error of the mean (as seen in the standard error of the mean equation on the equations page) as the denominator rather than the denominator shown here. Although the assumption of knowing population mean and population standard deviation may never be met in the real world, I find using this starting point as a leaping off point of the chapter on difference of means testing easier for students with little math background to grasp. With the simplified equation, I have my students calculate a "z obtained" when they then compare to a "z critical" (1.96 for alpha=.05 or 2.58 for alpha=.01). I would be interested in the opinions and experiences of others.Scott Huffmon 11:41, 7 July 2011 (PDT)