Exercise 1:
Does your doctor know? (part 5). In Exercises 14, 16, 18, and 20, we considered data on articles in the NEJM. The original study listed 23 different Statistics methods. (The list read: t-tests, contingency tables, linear regression, . . . .) Why would it not be appropriate to use chisquare methods on the 23 × 3 table with a row for each method?
Exercise 2:
Does your doctor know? (part 4). In Exercises 14, 16, and 18, we've tested a hypothesis about whether the use of statistics in NEJM medical articles has changed over time. The table shows the test s residuals.
a) Show how the residual for the 1989/No cell was calculated.
b) What can you conclude from the patterns in the standardized residuals?
Exercise 3:
Does your doctor know? (part 3). In Exercises 14 and 16, we've begun to examine whether the use of statistics in NEJM medical articles has changed over time.
a) Calculate the component of chi-square for the 1989/ No cell.
b) For this test, What's the P-value?
c) State your conclusion.
Exercise 4:
Does your doctor know? (part 2). The table in Exercise 14 shows whether NEJM medical articles during various time periods included statistics or not. We're planning to do a chi-square test.
a) How many degrees of freedom are there?
b) The smallest expected count will be in the 1989/No cell. What is it?
c) Check the assumptions and conditions for inference.
Exercise 5:
Does your doctor know? A survey7 of articles from the New England Journal of Medicine (NEJM) classified them according to the principal statistics methods used. The articles recorded were all non-editorial articles appearing during the indicated years. Let's just look at whether these articles used statistics at all.
Has there been a change in the use of Statistics over the decades?
a) What kind of test would be appropriate?
b) State the null and alternative hypotheses.