Problem 2
(a) z = 3.12, area = 0.0009
(b) 0.0018
(c) z = -2.05, x = 247.3
(d) z = +/- 1.15, between 247.41 and 247.59.
Problem 3
(b) There is a weak association.
(c) mean = 34.58, sd = 12.63
(d) (predicted BAC) = 0.2138 - 0.0002*(age in years)
(e) The predicted value is 0.21. Sixteen years is not too far from the observed data,
and the predicted value is a reasonable number.
Problem 4
False, the mean would be smaller.
Problem 5
False, within one standard deviation.
Problem 6
True.
Problem 7
False, data with a high correlation may still have a stronger non-linear relationship.
Problem 8
False, the slope is positive, but may not be one.
Problem 9
False, it indicates a mistaken calculation. -1 <= r <= 1.
Problem 10
True.
Problem 11
False, association is not causation.
Problem 12
False, influential points are usually far away from the mean.