A hypothesis test evaluating the effect of a treatment, makes the theoretical assumption that if there is a treatment effect it will ______.

1. have an average effect on the scores in the sample, and produce a sample mean that is close to the population mean.
2. have an average effect on the scores in the sample, and produce a sample mean that is unlikely to be drawn from the population by random chance.
3. increase the scores in the sample.
4. decrease the scores in the sample.