Be sure to check that the sum of the probabilities is 1 (it is!).
(a) Yes, it is a random sample because each student in any of the 5 classes is equally likely to be
included in the sample.
(b) No, it is not a simple random sample (SRS) because not all samples of size 25 are equally likely.
For example, in an SRS, one possible sample is having all 25 come from the same
class. Because we only take 5 from each class, this isn’t possible.
- The slope of the regression line is 0.8. For each additional milligram of the drug, reaction time is
predicted to increase by 0.8 seconds. Or you could say for each additional milligram of the drug,
reaction time will increase by 0.8 seconds, on average . - P (A or B) = P (A B) = P (A) + P (B) – P (A∩B) = 0.5 + 0.3 – P (A∩B) = 0.65 P (A∩B) =
0.15. Now, A and B are independent if P (A∩B) = P (A) · P (B). So, P (A) · P (B) = (0.3)(0.5) =
0.15 = P (A∩B). Hence, A and B are independent. - (a) Quantitative
(b) Qualitative
(c) Qualitative
(d) Quantitative
(e) Qualitative
(f) Quantitative
(g) Qualitative