The alternate hypothesis is the complement of the null hypothesis. The null hypothesis is what you anticipate through randomness. The alternative hypothesis, sometimes known as the alternate hypothesis is the opposite of the null hypothesis. The alternative hypothesis is what you would not anticipate through randomness. More often than not, you are trying to reject the null because you are trying to see a change in something – considering that most Six Sigma projects are trying to fix broken processes.
Use: Sometimes it might be a good idea to start off by writing down the alternative hypothesis. Usually we are trying to make a difference – to make an improvement – so writing the alternative hypothesis statement can make the process of writing the statements more intuitive. For example, the team theorizes (hypothesizes) method A will produce a more absorbent product than method B. In other words, what the team is saying is that when they are measuring the characteristic of some material to be more absorbent, method A will hopefully be found to be closer to a larger-is-better characteristic as compared to method B. Then, writing the null hypothesis is simply stating the opposite of the alternative hypothesis. In this case, the null hypothesis would be that both method A will be shown to be virtually the same as method B. (“Virtually” meaning that it is not significantly different – based upon statistics).
