Naked Economics Chapter 7

Homework assignment for chapter 5:
Problems 5.4 (page 177), 5.4 A die is thrown (1, 2, 3, 4, 5, 6) and a coin is tossed (H, T). (a) Enumerate the elementary events in the sample space for the die/coin combination. (b) Are the elementary events equally likely? Explain.

A) Elementary events are - DIE
COIN 1 2 3 4 5 6
HEADS H1 H2 H3 H4 H5 H6
TAILS T1 T2 T3 T4 T5 T6
B) YES, EACH EVENT IS EQUALLY LIKELY TO OCCUR. THERE ARE 12 POSSIBLE OUTCOMES AS A RESULT OF ROLLING OE DIE AND FLIPPING ONE COIN, THEREFORE THE LIKELYHOOD OF ANY ONE EVENT OCCURING IS 1/12.

5.13 (page 186),
5.13 Given P(A) = .40, P(B) = .50, and P(A ∩ B) = .05, find -
(a) P(A ∪ B)
P(A∪B)=P(A)+P(B)−P(A∩B)
= 0.40 + 0.50 - .05 = 0.85
(b) P(A | B)
P(A|B) =P(A∩B) for P(B)>0 P(B)
P(S’) = 1- P(S) = 0.783 / 0.217 = 3.608
P(S) P(S)

Problems 5.22 (page 190), 5.22 Which pairs of events are independent? a. P(A) = .60, P(B) = .40, P(A ∩ B) = .24. b. P(A) = .90, P(B) = .20, P(A ∩ B) = .18. c. P(A) = .50, P(B) = .70, P(A ∩ B) = .25.

5.23 (page 190) 5.23 The probability that a student has a Visa card (event V) is .73. The probability that a student has a MasterCard (event M) is .18. The probability that a student has both cards is .03. (a) Find the probability that a student has either a Visa card or a MasterCard. (b) In this problem, are V and M independent? Explain.

Problem 5.27 (page 197) 5.27 A survey of 156 introductory statistics students showed the following contingency table. Find each event probability. [pic] WebSurvey a. P(D) b. P(R) c. P(D ∩ R) d. P(D ∪ R) e. P(R | D) f. P(R | P) [pic]

Problem 5.33 (page