Statistics for People Who (Think They) Hate Statistics

by Neil J. Salkind

have to assume that there is no difference. And a statement of no difference or no relationship is exactly what the null hypothesis is all about. Such a statement ensures that (as members of the scientific community) we are starting on a level playing field with no bias toward one or the other direction as to how the test of our hypothesis will turn out. Furthermore, if there are any differences between these two groups, then you have to assume that these differences are due to the most attractive explanation for differences between any groups on any variable—chance! That’s right: Given no other information, chance is always the most likely and attractive explanation for the observed differences between two groups or the relationship between variables. Chance explains what we cannot. You might have thought of chance as the odds of winning that $5,000 jackpot at the penny slots, but we’re talking about chance as all that other “stuff” that clouds the picture and makes it even more difficult to understand the “true” nature of relationships between variables.