As I’ve mentioned in class, a normal distribution is assumed for almost all of the statistics we use in psychology.  Because non-normal data can influence our results, we must check to make sure the assumption is fulfilled.

The easiest way to do this is simply to create a histogram and compare it to the normal curve by simply looking at it.  SPSS will actually plot a normal curve right on top of your data, so its easy to see big deviations.