From Chapter 9
The correct answer is (a).
μ X+Y is correct for any random variables X and Y . However, σ X+Y is correct only if X and Y are
independent .
- From Chapter 14
The correct answer is (a). Because 0 is not in the interval (0.45, 0.80), it is unlikely that the true
slope of the regression line is 0 (III is false). This implies a non-zero correlation coefficient and the
existence of a linear relationship between the two variables. - From Chapter 10
The correct answer is (c). This is a geometric setting (independent trials, each succeeding or failing
with the same probability).
(On the TI-83/84, this is found as geometpdf(18/38,8) .)
From Chapter 8
The correct answer is (e). The choice is made here to treat plots A and B as a block and plots C and
D as a block. That way, we are controlling for the possible confounding effects of the river. Hence the
answer is (c). If you answered (e), be careful of confusing the treatment variable with the blocking
variable.
- From Chapter 6 The correct answer is (c).
They are both below average, but Grumpy’s z score puts him slightly above Dopey. Note that if
Grumpy had been 4 points above the mean on the first test and Dopey 5 points above the mean on the
second, then Dopey would have done slightly better than Grumpy.
From Chapter 12
The correct answer is (b).
The standard error of for a test of H 0 : p = p 0 isIf you got an answer of 0.0645, it means you used the value of rather than the value of p 0 in the
formula for s.