Exercises 169following data, all children who were ever classified as exhibiting behavior associated with
ADD have been combined into one group (labeled ADD):
Remedial English Nonremedial English
Normal 22 187 209
ADD 19 74 93
41 261 302
Does behavior during elementary school discriminate class assignment during high
school?6.11 Use the data in Exercise 6.10 to demonstrate how chi-square varies as a function of sample size.
a. Double each cell entry and recompute chi-square.
b. What does your answer to (a) say about the role of the sample size in hypothesis
testing?6.12 In Exercise 6.10 children were classified as those who never showed ADD behavior and
those who showed ADD behavior at least once in the second, fourth, or fifth grade. If we do
not collapse across categories, we obtain the following data:
2nd & 2nd & 4th & 2nd, 4th, &
Never 2nd 4th 4th 5th 5th 5th 5th
Remedial 22 2 1 3 2 4 3 4
Nonrem. 187 17 11 9 16 7 8 6a. Run the chi-square test.
b. What would you conclude, ignoring the small expected frequencies?
c. How comfortable do you feel with these small expected frequencies? If you are not
comfortable, how might you handle the problem?6.13 In 2000, the State of Vermont legislature approved a bill authorizing civil unions between
gay or lesbian partners. This was a very contentious debate with very serious issues raised
by both sides. How the vote split along gender lines may tell us something important about
the different ways in which males and females looked at this issue. The data appear below.
What would you conclude from these data?
Vote
Yes No Total
Women 35 9 44
Men 60 41 101
Total 95 50 1456.14 Stress has long been known to influence physical health. Visintainer, Volpicelli, and
Seligman(1982) investigated the hypothesis that rats given 60 trials of inescapable shock
would be less likely later to reject an implanted tumor than would rats who had received 60
trials of escapable shock or 60 no-shock trials. They obtained the following data:
Inescapable
Shock Escapable Shock No Shock
Reject 8191845
No Reject 22 11 15 48
30 30 33 93What could Visintainer et al. conclude from the results?