Nt1330 Unit 3

A survey is conducted in Chicago (population 2,800,000) using random-digit-dialing equipment which place calls at random to residential phones, both mobile and landline. The purpose of the survey is to determine the percentage of adults who would favor a half-cent increase in the sales tax to help fund public transportation. Four hundred adults are interviewed and 36% of them favor the proposal. Answer the next two questions.

1. The sample size for this sample survey appears to be a) 400 b) 2,800,000 c) 144 d) 1,008,000

2. The 36% is a a) Parameter b) Margin of error c) Chance of 144 people agreeing to the statement d) Statistic

3. Event A occurs with probability 0.05. Event B occurs with probability
4. Event A occurs with probability 0.05. Event B occurs with probability 0.75. If A and B are independent, which statement is true. e) P(A and B) = 0 a) P(A or B) = 0.80 b) P(A and B) = 0.0375 c) Both (a) and (b) are true.

A marketing research firm wishes to determine if the adult men in Laramie, Wyoming would be interested in a new upscale men's clothing store. From a list of all residential addresses in Laramie, the firm selects a simple random sample of 100 and mails a brief questionnaire to each. Use this information to answer the next three questions.

5. The population of interest is a) all adult men in Laramie, Wyoming. b) all residential addresses in Laramie, Wyoming. c) the members of the marketing firm that actually conducted the survey. d) the 100 addresses to which the survey was mailed.

6. The sample in this survey is a) all adult men in Laramie, Wyoming. b) all residential addresses in Laramie,
Suppose this commuter is working 5 days a week. How many times during a week would she expect to stop at a red light on her way to work? a) 10 b) 2.35 c) 11.75 d) 4

17. Suppose X is a random variable with mean µX and standard deviation σX. Suppose Y is a random variable with mean µY and standard deviation σY. The mean of X + Y is a) µX + µY. b) (µX/σX) + (µY/σY). c) µX + µY, but only if X and Y are independent. d) (µX/σX) + (µY/σY), but only if X and Y are independent. 18. Suppose X is a random variable, with mean µX and standard deviation σX. Suppose Y is a random variable, with mean µY and standard deviation σY. The variance of X + Y is a) σX + σY. b) (σX)2 + (σY)2. c) σX + σY, but only if X and Y are independent. d) (σX)2 + (σY)2, but only if X and Y are independent.

Suppose the probability that a U.S. resident has traveled to Canada is P(C) = 0.18, to Mexico is P(M) = 0.09, and to both is 0.04. Use the Venn diagram to answer questions the next four questions.

19. What is the probability that an American chosen at random has traveled to either Canada or Mexico or both? a)