Section 6.3 Learning Check|Please refer to the following explanation for the questions 1-2. <br> Two different groups of medical researchers are working on a new treatment for a certain type of cancer. The average survival time after diagnosis on the standard treatment is two years.<br> Research group A tries the new treatment on three subjects who have an average survival time after the diagnosis of four years. <br> Research group B tries the new treatment on 10,000 subjects who have an avrage survival time after diagnosis of 2 years and 1 day. |Please enter your Full Name:|Your Email Address:|Your ID Number or Password:|For the research group A, although the survival time is doubled, the results are not statistically significant even at a high level of significance. The explanation is # the placebo effect is present, which limits statistical significance. %% the sample size is small. %% that although the survival time has doubled, in reality the actual increase is two years. %% the calculation was in error. The researchers forgot to include the sample size. %%|For the research group B. Although the difference is quite small, the effect was statistically significant. The explanation is # that new treatments typically have more variability than standard treatments. %% that the sample size is very large. %% that the mean of 2 is small. %% all of the above. %%|You obtain a P-value of 0.052, and the selected significance level is 0.05. Which of the following is true? # At the 5&KPHHASH37; significance level, you have proved that the null hypothesis is true. %% You have failed to obtain evidence against the null hypothesis. %% There is some evidence against the null hypothesis, and a study using a larger sample size may be worthwhile. %% This should be viewed as a pilot study, and the data suggests that further investigation of the hypotheses will not be fruiful at the 5&KPHHASH37; significance level. %%|In assessing the validity of any test of hypotheses, it is good practice to # examine the probability model that serves as a basis for the test by using exploratory data analysis on the data. %% determine exactly how the study was conducted. %% determine what assumptions the researchers made. %% all of the above. %%