What an easy way to remember alternative and null hypothesis?
Let’s take an example of a research study. Let’s say that you believe that a high fat diet leads to weight gain. You construct a study whereby participants are fed either a high fat or a low fat diet for a given period of time. You need to start with the null hypothesis. Your null hypothesis is that fat has nothing to do with weight gain (essentially). Remember “null” as “no” (they sound similar). Your null hypothesis says there is NO difference (e.g., there will be no significant difference in weight gain among participants fed a high fat diet and those fed a low fat diet). The “alternative” is the ALTERNATIVE to no difference (i.e., there IS a difference). The alternative hypothesis is what you EXPECT is going to happen (e.g., people fed a high fat diet will report higher weight gains than those given a low fat diet). You REJECT THE NULL if your p< .01 (or .05 or wherever you set your alpha). The "p" tells you HOW LIKELY IT IS THAT YOU ARE CORRECT. In the case of the null hypothesis,
