Statistics 2nd Exam 2019

Univesity of Jordan Mathematics Department Principles of Statistics 0301131 2nd Exam 24/04/2009 5-6 Lecturer: Number: Name: Time: 0301131 Multiple Choice ( 2 points eaclt) Identify the Leiter of the choice that best completes the statemenJ or answers the question. 1. If X - B(I00,0.2), then P(X < 27) = ~ 0.9098 b. 0.9244 d. 0.9332 2. (if the probability of hitting a target for each sing e trial is 0.7, then the probability of hitting the target for the l.flrst time in the third trial is 0.063 a. 0.028 b. 0.103 d. 0.167 3. A box contains 2 white balls, l black ball and 2 re ball. If we draw two balls without replacement, then the probability of getting I \ · a a. 5/10 c. 4/10 b. 6/10 d. 7/10 a. 4. In a class 40% of th dents are math and 60% are physics. 50% of the math students passed the test and~ 70% of the physics students passed the test. If we choose a student randomly, the probability that he (she) passed the test is ~~ a. 0.57 c. 0.55 l_,d-0.62_../ b. 0.59 ~ 5. The weights (in kgs) of male students are normally distributed with mean 74 and variance 25. Choosing a stu enttan omly, the probability that his weight is greater than 68 kgs is c. 0.1151 0.8849 b. 0.7683 d. 0.23 17 and Y be discrete random variables with a joint probability function f given by the following table: 6. y 0 1 2 x c 2 0 1/3 E(XY)= a. 4/2 7. l/6 0 1/3 1/6 ~ d. 1/2 ~ 2 Let X and Y be discrete random variables with E(X) = 9, E(Y ) = 20, Var Y = 16, E(XY) = 45 and E(Y)> O, b. then Cov (2X-1, 5-3Y)Qa. 73 . 8. A a. screte andom variao 436 b. 5/2 - 16 c. - 67 d. 144 as mean 20 and standard deviation 4. E( X(X+ 1) ) = 426 c. 416 d. 446 • .. Essay 9. ( 4 points) The grades of students have mean 72 and standard deviation 9. If we choose a sample of 36 students, find the probability that the sum of their grades is greater than 2700. I 0. ( 5 points) A multiple choice exam consists of l 0 questions, each question has 5 choices, only one of them is correct. A student answers randomly, find the probability that he will get more than 6 WRONG answers. 11. ( 5 points) Tossing a fair coin twice, let X be the number of heads that appear. Find E(X). 2 Univesity of Jordan Mathematics Department Principles of Statistics 0301131 2nd Exam 24/04/2009 5-6 Name: Lecturer: Number: Time: 0301131 Multiple Choice ( 2 points each) Identify the letter of the choice that best completes the statement or answers the question. 1. In a class 40% of the students are math and 60% are physics. 50% of the math students passed the test and 70% of the physics students passed the test. If we choose a student randomly, the probability that he (she) ~ passed the test is ~ a. 0.59 b. 0.55 c. 0.57 2. Let X and Y be discrete random variables with E(X) = 9, E(Y 2 ) = 20, Var Y = 16, E(XY) = 45 and E(Y)> O, then Cov (2X-l, 5-3Y) = a. 144 b. r.- ___"- 73 c. -67 ~ 3. A box contains 2 white balls, 1 black ball and 2 red bal l. If we draw two balls without replacement, then the probability of getting~hite balh ). a. 4/10 b. 6/10 c. 5/10 d. 7/10 --- - 4. let X and Y be discrete random variables with a joint probability function f g iven by the following table: y 0 2 1 x l 2 0 l/6 1/3 0 1/3 116 E(XY)= ~ ·- \ a. 4/2 c. 112 d. 5/2 -~ 5. If the probability of hittin a target for each single trial is 0.7, then the probability of hitting the target for the rsrtlme . he third trial is 0.063 b. 0.028 c. 0.167 d. 0.103 6 discrete random variable has mean 20 and st~iation 4. E( X(X+ l)) = ~ a. 426 b. 446 d. 416 7. If X- B( I00, 0.2), then ~ ~ a. 0.9332 c. 0.9098 d. 0.9244 8. The weights (in kgs) of male students are normally distributed with mean 74 and variance 25. Choosing a student random ly, the probabi lity that his weight is greater than 68 k~ - - ~ a. 0.2317 b. 0.7683 c. 0.1151 ~ .. univesity of Jordan Mathematics Department Principles of Statistics 0301131 2nd Exam 24/04/2009 5-6 Lecturer: Number·: Name: Time: 0301131 Multiple Choice ( 2 points each ) Identify the letter of the choice that best completes the statement or answers the question. ~ I. If the probability of hitting a target for each single trial is 0.7, then the probability of h itting the target for the I is ~e (a, first time in the third tria~ . 0.063 a. 0.028 c. 0.167 d. 0.103 2. ?J!(IQ . 1-) 0.2), then P b. 0.9484 3. y <27) = 0.9332 tJ """'-'"'- <>-ff c. d. 0.9244 ~'j\'V·t 0.9098 and Y be discrete random variables with a joint probability function f given by the following table: 2 I 0 x 1 2 G 0 113 116 0 113 116 b. 512 c. l /2 d. 4. Let X and Y be discrete random variables with E(X) = 9, E(Y then Cov (2X-1, 5-3Y) = b. -67 a. 73 c. 144 2 ) 4/2 ./ = 20, Var Y = 16, E(XY) = 45 and E(Y)>O, c ~ ~ ~ 5. A box contains 2 white balls, 1 black ball and 2 red ball. If we draw two balls without replacement, then the probability of getting 1 white ball is ~ b. 4/10 d. 7/1 0 "-) a. S/10 ~ 6. T he weights (in kgs) of male students are normally distributed with mean 74 and variance 25. a ) f-d~mly, the probability that his weight is greater than 68 kgs is rV ( 1 l.f1 1-1' f(:t >tll) c. 0.7683 ~ b. 0.1151 d. 0.2317 (J ) ( () C~osing iscrete random varia~ha~ 20 and standard deviation 4. E( X(X+l)) = a. 426 436 ~ c. 416 d. 446 8. In a class 40% of the s~ath and 60% are physics. 50% of the math students passed the test and 70% of the physics students passed the test. If we choose a student ragndomly the probability that he (she) passed the test is a. 0.59 b. 0.57 c. 0.55 d. 0.62 7. L Vh'()f)'L~ v( ?~ 0)) o- )~ (.). b , p(m""+h)-:...o·\,I lf ( p( P\:y·1'U \ ?~) ~ -1- lf 0 ~.\,~ (WJ) ~ 6-i s a• \'I P,,_...,l ~ f ( p°"'' ""-..1h ) -== 'I ( (, ' ':>} -t -==-- b .'L \ u -+ () l'L I 6. -t fI l ( (, ' ~ ) '11- ~"~) n n l '), ':J ,-,-"' ) - .. Essay ~· ( 4 points) The grades of students have mean 72 and standard deviation 9. If we choose a sample of 36 students, find the probability that the sum of their grades is greater than 2700. I 0. ( 5 points ) A multiple choice exam consists of 10 questions, each question has 5 choices, only one of them is correct. A student answers randomly, find the probability that he will get more than 6 WRONG answers. 11. x. \ 2