Sample Space - Advanced Quantitative Methods - Exam, Exams of Mathematics

This is the Past Exam of Advanced Quantitative Methods which includes Sample Space, Interviewed Agrees, Response Combination, Furniture Store, Furnish, Models, Technicians, Salaries, Problems etc. Key important points are: Sample Space, Interviewed Agrees, Response Combination, Furniture Store, Furnish, Models, Technicians, Salaries, Problems, Four Digit Number

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Winter 2010 Final Exam 201-301RE
Page 1 of 5
Show all steps if possible
Marks for each question are included in [ ]on the right, [total marks/80]
Give answers to 2 decimal places unless otherwise noted
1. A political scientist asked a group of people how they felt about two political policy statements. Each
person was to respond A (agree), N (neutral), or D (disagree) to each policy statement. [4]
a. Describe the sample space; that is, list all possible response combinations to the two statements.
b. Assuming each response combination in the sample space is equally likely, what is the probability
the person being interviewed agrees with at least one of the two policy statements?
c. Assuming each response combination in the sample space is equally likely, what is the probability
the person being interviewed agrees with exactly one of the two political policy statements?
d. Assuming each response combination in the sample space is equally likely, what is the probability
the person being interviewed agrees with the two political policy statements?
2. An interior decorator must furnish two offices. Each office must have a desk, a chair, and a file cabinet . At
a local office furniture store there are 6 models of desks, 8 models of chairs, and 4 models of file cabinet ,
all of which are compatible. (Any desk can be matched with any chair, etc.) [4]
a. How many choices does the decorator have if he wants to select two desks, two chairs, and two file
cabinets if he doesn’t want to select more than one of any model?
b. How many ways can he hire two technicians with different salaries from a group of 20 all equally
qualified ?
3. Ryan prepares for an exam by studying a list of 20 problems. He can solve 12 of them. For the exam, the
instructor selects ten questions at random from the list of twenty. [6]
a. In how many ways can 10 problems be chosen from the 12 that Ryan can solve?
b. In how many ways can the 10 problems be chosen from all the 20 problems on the list?
c. What is the probability that Ryan can solve all ten problems on the exam?
4. We must form a four-digit number using the digits 1, 2,3,4,5 without repetitions. How many numbers can
be created? [2]
5. A group of forty people at a health club were classified according to their gender and smoking habits, as
shown in the table below. One person is selected at random from that group of forty people. [7]
Smoking Habits
Gender
Smoker (S)
Nonsmoker (N)
Total
Male (M)
2
24
26
Female (F)
6
8
14
Total
8
32
40
a. What is the probability the person does not smoke?
b. What is the probability the person is female?
pf3
pf4
pf5

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Show all steps if possible Marks for each question are included in [ ]on the right, [total marks/80] Give answers to 2 decimal places unless otherwise noted

  1. A political scientist asked a group of people how they felt about two political policy statements. Each person was to respond A (agree), N (neutral), or D (disagree) to each policy statement. [4]

a. Describe the sample space; that is, list all possible response combinations to the two statements. b. Assuming each response combination in the sample space is equally likely, what is the probability the person being interviewed agrees with at least one of the two policy statements? c. Assuming each response combination in the sample space is equally likely, what is the probability the person being interviewed agrees with exactly one of the two political policy statements? d. Assuming each response combination in the sample space is equally likely, what is the probability the person being interviewed agrees with the two political policy statements?

  1. An interior decorator must furnish two offices. Each office must have a desk, a chair, and a file cabinet. At a local office furniture store there are 6 models of desks, 8 models of chairs, and 4 models of file cabinet , all of which are compatible. (Any desk can be matched with any chair, etc.) [4] a. How many choices does the decorator have if he wants to select two desks, two chairs, and two file cabinets if he doesn’t want to select more than one of any model? b. How many ways can he hire two technicians with different salaries from a group of 20 all equally qualified?
  2. Ryan prepares for an exam by studying a list of 20 problems. He can solve 12 of them. For the exam, the instructor selects ten questions at random from the list of twenty. [6] a. In how many ways can 10 problems be chosen from the 12 that Ryan can solve? b. In how many ways can the 10 problems be chosen from all the 20 problems on the list? c. What is the probability that Ryan can solve all ten problems on the exam?
  3. We must form a four-digit number using the digits 1, 2,3,4,5 without repetitions. How many numbers can be created? [2]
  4. A group of forty people at a health club were classified according to their gender and smoking habits, as shown in the table below. One person is selected at random from that group of forty people. [7]

Smoking Habits Gender Smoker (S) Nonsmoker (N) Total Male (M) 2 24 26

Female (F) 6 8 14

Total^8 32

a. What is the probability the person does not smoke? b. What is the probability the person is female?

c. What is the probability the person is female and does not smoke? d. If the person was female, what is the probability she does not smoke. e. What is the probability the person is female or does not smoke?

  1. Lily frequents one of two fast food restaurants, choosing McDonald 25% of the time and Burger King 75% of the time. If she goes to McDonald, she buys French Fries 10% of the time, and if she goes to Burger King, she buys French Fries 80% of the time [4] a. The next time Lily goes into a fast food restaurant, what is the probability that she goes to McDonald and orders a French Fries? b. If Lily goes to a fast food restaurant ,and orders French Fries, what is the probability that she is at Burger King?
  2. A computer repair shop has two work centers. The first center examines the computer to see what is wrong, and the second center repairs the computer. Let x 1 and x 2 be random variables representing the lengths of time in minutes to examine a computer x 1 and to repair a computer x 2. Assume x 1 and x 2 are independent random variables. Long term history has shown the following times:

Examine computer x 1 :  1 =28.1 minutes;  1 =8.2 minutes ; Repair a computer: x 2 :  2 =90.

minutes;  2 =15.2 minutes [6]

a. Let W= x 1 + x 2 be a random variable representing the total time to examine and repair the computer. Calculate the mean , variance and standard deviation for the random variable W b. There is a flat rate of $1.50 per minute to examine the computer, and if no repairs are ordered, there is also an additional $50 service charge. Let L=1.5 x 1 +50. Calculate the mean , variance and standard deviation for the random variable L

  1. Let x denote the weight gain in pounds per month for a calf. The probability distribution of x is shown below. [3]

a. Find the expected average weight gain in pounds per month for a calf? b. Find the variance of the weight gain. c. What is P( x 5)?

  1. A quiz consists of 5 multiple choice questions. Each question has 5 choices, with exactly one correct choice. A student, totally unprepared for the quiz, guesses on each of the 5 questions. [4]

a. How many questions should the student expect to answer correctly? b. What is the standard deviation of the number of questions answered correctly? Give answer to three decimal places

x p( x ) 0 0. 5 0. 10 0. 15 0.

  1. A systems specialist has studied the work flow of clerks all doing the same inventory work. Based on this study, she designed a new work-flow layout for the inventory system. To compare average production for the old and new methods, a random sample of six clerks was used. The average production rate (number of inventory items processed per hour) for each clerk was measured both before and after the new system was introduced. The results are shown in the accompanying table. Assuming that the work rate is normally distributed, test the claim that the new system speeds up the work rate. Use a 5% significance level. [6]

Clerk 1 2 3 4 5 6 Rate in old system 110 100 97 85 117 101 Rate in new system 120 112 115 83 125 109

a. State the null and the alternate hypotheses. b. What is the value of the sample test statistic? c. Find (or estimate) the P -value. d. State your conclusions in the context of the application.

  1. A study of hypertension involved two groups of men between the ages of 30 and 60. The first group consisted of a random sample of 42 men who had demanding jobs and control of them, such as executives. The second group consisted of a random sample of 53 men who also had demanding jobs, but who had little control over their jobs. In the first group the average systolic blood pressure was 138 with standard deviation 5. In the second group the average systolic blood pressure was 145 with standard deviation 7. Test the hypothesis that the mean systolic blood pressure for men in the second group is higher than the mean systolic blood pressure for men in the first group. Use a 5% level of significance. [6]

a. State the null and the alternate hypotheses. b. What is the value of the sample test statistic? c. Find (or estimate) the P -value. d. State your conclusions in the context of the application.

  1. A lake in northern Quebec was stocked with fish. Seven years later samples were taken to see if the distribution had changed. Use the following results to test whether the distribution of fish has changed at the 0.01 level of significance. [6]

Type of fish Percentage stocked Number of fishes sampled after seven years Bass 30% 150 Carp 25%^180 Perch 5% 30 Trout 40% 300

a. State the null and the alternate hypotheses. b. What is the value of the sample test statistic? c. Find (or estimate) the P -value. d. State your conclusions in the context of the application.

Answers:

  1. a) The sample space is S = {AA, AN, AD, NA, NN, ND, DA, DN, DD}. b) 5/9 0.556; c) 4/9 0.444; d) 1/9 0.

  2. a) Number of choices the decorator has = C 2^6  C^82  C 24 =(15)(28)(6)=2520; b) P 220 =

  3. a) C 1012 C 08 ; b) C 1020 ; c) 20

10

8 0

12 10 C

C C

  1. a) P(N) = 32 / 40 = 0.80; b) P(F) = 14 / 40 = 0.35; c)P(F N) = 8 / 40 = 0.20; d) P(N / F) = P(F N) / P(F) = 0.2 / 0.35 = 0.5714 ; e) P ( FN ). 35 . 8 . 2 . 95

  2. a) Define the following events: M : Lily chooses McDonald, B : Lily chooses Burger King, and F : Lily orders French Fries. Then, P( M ) = 0.25, P( B ) = 0.75, P( F / M ) = 0.10, and P( F / B ) =0.8. Therefore, P(M F) = P( M ).P( F / M ) = (0.25)(0.1) = 0.025. b) P( B / F ) = P( B F ) / P( F ) = P( B ). P( F / B ) / P( F ) = (0.75)(0.8)/0.625=0.

7) a)  w  28. 1  90. 5 =118.6minutes ;  w^2  8. 22  15. 22 =298.28;  L   w^2 =17.27minutes

b)  L  50  1. 5 ( 28. 1 )=92.15 minutes;  L^2  1. 528. 22 =151.29;  L  12. 3 minutes

8) a)    x p x  ( ) = 7 pounds; b) ^2   ( x  )^2  p x ( )= 16;

c) P( x 5) = P( x = 5) +P(x=10)+P(x=15)= 0.

  1. a) μ = np = 1; b) σ = npq = 0.894; c) P( x ≥ 3) = 0.

  2. a) P(x > 450) = 0.1788; (b) P( (^) x > 450) = 0.

  3. a) P ( x ≥ 49.5) = P ( z ≥ – 2.02) = 0.9783;(b) P (49.5 < x < 65.5) = P (–2.02 < z < 1.97) = 0.

    1. 55 lb  1. 85 lb
    1. 65  p  0. 81
  4. (a) H0: μ = 10.7 oz; H1: μ > 10.7 oz ; (b) t = 1.7166 ; (c) P value is between 0.05 and 0.075.

(d) Do not reject H0. We cannot conclude that the mean weight of all packages mailed this week is greater than 10.7 oz.

  1. (a) H0: p = 0.55; H1: p < 0.55; (b) z = – 3.05; (c) P value= 0.0011 ;

(d) Reject H0. Fewer than 55% of all voters favor the project.

16) (a) H0:  d = 0; H1:  d < 0 (  old   new  0 );(b) t = -3.37; ( d = -9; s = 6.5421)

(c) P value between 0.005 and 0.010; (d) Reject H0. The mean work rate is higher with the new work- flow system.

  1. (a) H0: μ 1 = μ 2 ; H 1 : μ 1 < μ (^2) ; (b) t = – 5.68 ;(c) P value < 0.

(d) Reject H0. The systolic blood pressure for the second group is higher.

  1. (a) H0: The distribution of fish has not changed. H1: The distribution of fish has changed.

(b) ^2 = 18. (c) p-value < 0. (d) Reject H0. The distribution of fish has changed.