# Midterm Exam

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STAT 1770 MIDTERM-2

Date: March 19, 2010 Time: 12 30- 14 30 Instructions 1. This is a closed book exam.

Name: _______________ I.D. #: _______________

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PART A MULTIPLE CHOICE QUESTIONS

(31 Points)

1. Which method of data collection is involved when a researcher counts and records the number of students wearing backpacks on campus in a given day? a. An experiment. b. A survey. c. Direct observation. d. None of these choices. 2. A marketing research firm selects a random sample of adults and asks them a list of questions regarding their beverage preferences. What type of data collection is involved here? a. An experiment. b. A survey. c. Direct observation. d. None of these choices. 3. A researcher conducts a study where she divides subjects into two groups, gives each group a certain treatment, and records their responses. What type of data collection is being used here? a. An experiment. b. Direct observation. c. A survey. d. A census. 4. When the population is divided into mutually exclusive sets, and then a simple random sample is drawn from each set, this is called: a. simple random sampling. b. stratified random sampling. c. cluster sampling. d. selection bias. 5. To give away a door prize, the host of a dinner party put each person's name into a hat, mixed them up, and selected one name. What sampling method was used? a. Simple random sample b. Systematic sample c. Stratified random sample d. Cluster sample 6. The collection of all possible outcomes of an experiment is called: a. a simple event b. a sample space c. a sample d. a population

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7. If event A and event B cannot occur at the same time, then A and B are said to be a. mutually exclusive b. independent c. collectively exhaustive d. None of these choices. 8. The probability of the intersection of two events A and B is denoted by P(A and B) and is called the: a. marginal probability b. joint probability c. conditional probability of A given B d. conditional probability of B given A 9. If the outcome of event A is not affected by event B, then events A and B are said to be a. mutually exclusive b. independent c. collectively exhaustive d. None of these choices. 10. If A and B are independent events with P(A) = 0.4 and P(B) = 0.6, then P( A and B)= a. 0.76 b. 1.00 c. 0.24 d. 0.20 11. If A and B are independent events with P(A) = 0.2 and P(B) = 0.6, then P( A OR B) a. 0.62 b. 0.12 c. 0.60 d. 0.68 12. If A and B are independent events with P(A) = 0.05 and P(B) = 0.65, then P(A  B) = a. 0.05 b. 0.0325 c. 0.65 d. 0.8 13. If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P( A and B) a. 0.30 b. 0.15 c. 0.00 d. 0.20

4 14. If A and B are mutually exclusive events with P(A) = 0.3 and P(B) = 0.5, then P( A OR B) a. 0.00 b. 0.15 c. 0.8 d. 0.2 15. Events A and B are mutually exclusive with P(A) = 0.3 and P(B) = 0.2. Then, P(Bc) = a. 0.00 b. 0.06 c. 0.7 d. 0.8 16. An experiment consists of four outcomes with P(E1) = 0.2, P(E2) = 0.3, and P(E3) = 0.4. The probability of outcome E4 is a. 0.500 b. 0.024 c. 0.100 d. 0.900 17. If P(A) = 0.58, P(B) = 0.44, and P (A and B) = 0.25, then P( A OR B) = a. 1.02 b. 0.77 c. 0.11 d. 0.39 18. If P(A)...