Allergic reactions to poison ivy can be miserable. Plant oils cause the reaction.

withinafter

ReactionWithin 5 MinutesAfter 5 MinutesRow TotalNone

Mild

Strong394

61

4555

336

109449

397

154Column Total5005001000

WANMS

(a)P(N)P(M)P(S)

(b)P(N | W)P(S | W)

(c)P(N | A)P(S | A)

(d)P(N and W)P(M and W)

(e) P(N or M). 

Are the events N = no reaction and M = mild reaction mutually exclusive? Explain.

Yes. P(N or M) = 0.

Yes. P(N and M) = 0.

No. P(N and M) ≠ 0.

No. P(N or M) ≠ 0.

(f) Are the events N = no reaction and W = washing oil off within 5 minutes independent? Explain.

No. P(N and W) ≠ P(N) · P(W).

No. P(N and W) = P(N) · P(W).

Yes. P(N and W) ≠ P(N) · P(W).

Yes. P(N and W) = P(N) · P(W).