A researcher conducted a study to investigate effect of weight loss for patients taking diet A and diet B. : = vs. : <. The null hypothesis was highly significant (rejected) at < 0.001. Select all the correct answers.
(a) The difference for these two diets must be very large.
(b) The difference for these two diets may or many not be large.
(c) One diet is 1000 times more effective than the other.
(d) One diet is more effective than the other but the magnitude of the effect is not known.