The Other Ninety Nine Samples

Master Stem was inspecting his students work. Student Leaf displayed a 95% confidence interval from a randomized control trial. "What does this confidence interval tell you?" Master Stem inquired.

Student Leaf replied, "This interval contains the value of zero, which provides evidence that there is no difference between the treatment group and the control group."

"And what can you tell me about the truth of this interval, Student Leaf."

"We cannot make a probability statement about this particular interval, Master Stem. We can say, however, that if I collected 100 samples and computed confidence intervals using this method, about 95% of them would contain the true mean difference."

"Very interesting, Student Leaf. Now that you have collected the first sample, when do you plan on collecting the other 99?"

Creative Commons License This work is licensed under a Creative Commons Attribution 3.0 United States License. It was written by Steve Simon and was last modified on 2017-06-15. Category: Teaching resources