Imagine that a researcher performs an experiment examining the effects of nutrition on memory. each subject is randomly assigned to one of three groups: high-protein diet; high-fiber diet; standard diet (control). after a month on this diet, each subject undergoes a memory test. the experimenter finds that memory performance is somewhat better for the high-protein and high-fiber groups than for the control group, but the effect of nutrition is not statistically significant. thus, the experimenter accepts the null hypothesis. the experimenter hypothesizes that the effect was weak because the experiment was only 1 month long. a new experiment is then conducted that is identical to the first, except with 3 months on the diet. now a significant effect of nutrition is found. from these two experiments, the experimenter is justified in concluding that: [select two that are correct]