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Preguntas del test (131)
1Let random variable X be normal with parameters mean=5, variance=9. Which of the following is a standard normal variable?
- AZ=(X-5)/5
- BZ=(X-3)/5
- CZ=(X-5)/3
- DZ=(X-3)/3
- ENone of these
2A bag has six red marbles and six blue marbles. If two marbles are drawn randomly from the bag, what is the probability that they will both be red?
- A1/2
- B11/12
- C5/12
- D5/22
- E1/3
3Two dice are rolled, find the probability that the sum is less than 13.
- A1
- B1.2
- C0.5
- D0.6
- E0.8
4Probability mass function for discrete random variable X is represented by the
graph. Find Var(X).
- A1
- B4
- C5
- D2
- E6
5A man can hit a target once in 4 shots. If he fires 4 shots in succession, what is the probability that he will hit his target?
- A175/256
- B1
- C1/256
- D81/256
- E144/256
6Find P(X>0.5). The joint distribution for two random variables X and Y is given by.
- A0.5
- B0.25
- C0.15
- D0.75
- E0.1
7Find the expected value of random variable X. Let X be continuous random variable with probability density function .
- A19/3
- B13/3
- C12/7
- D28/9
- E27/4
8Let f(x,y) = x + y, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, be the joint PDF of X and Y. Compute E[2X].
- A7/6
- B0
- C1
- D7/12
- E1/6
9Let f(x,y) = x + y, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, be the joint PDF of X and Y. Compute E[Y].
- A0.2
- B0.823
- C0.583
- D1
- E0
10Let f(x,y) = x + y, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, be the joint PDF of X and Y. Compute E[X].
- A0.2
- B0.823
- C0.583
- D1
- E0
11Let f(x,y) = x + y, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, be the joint PDF of X and Y. Find the marginal PDF of Y.
- Ay+1/2
- By
- C1/2y
- Dy^2/2
- E1/2
12From a group of 5 men and 6 women, how many committees of size 3 are possible with two men and 1 woman if a certain man must be on the committee?
- A(5 1) x (6 1)
- B(4 1) x (1 1) x (6 1)
- C(1 1) x (6 1)
- D(5 2) x (6 1)
- ENone of these
13If A and B are two mutually exclusive events with P(A) = 0.15 and P(B) = 0.4, find the probability P(A and Bc) (i.e. probability of A and B complement).
- A0.4
- B0.15
- C0.85
- D0.6
- E0.65
14The Cov(aX,bY) is equal to
- AaCov(X, Y) + bCov(X, Y)
- BaCov(X, Y) - bCov(X, Y)
- CabCov(X, Y)
- Da²b²Cov(X, Y)
- Ea/b*Cov(X, Y)
15The joint density function for the random variables X and Y is given by. Find E[X].
- A0
- B1
- C1.4142
- D2
- ENone of these
16Find E[X+Y].
- A1/6
- B6/7
- C7/6
- D5/6
- E0
17Find E[X-Y].
- A0
- B7/6
- C2/3
- D1/6
- ENone of these
18Let X be the random variable for the life in hours for a certain electronic device. Find the expected life for a component.
The probability density function is: (picture)
- A2000 hours
- B1000 hours
- C100 hours
- D200 hours
- ENone of these
19The random variable X has the continuous CDF
- A16/9
- B4/3
- C4/9
- D5/9
- E2/3
20If Z is normal random variable with parameters µ=0, σ²=1 then the value of c such that P(|Z|<c)=0.7994 is
- A1.28
- B0.84
- C1.65
- D2.33
- ENone of these
21Assume that Z is standard normal random variable. What is the probability P(|Z|>2.53)?
- A0.9943
- B0.0114
- C0.0057
- D0.9886
- ENone of these
22The joint distribution for two random variables X and Y is given by. Find the E[Y].
- A1
- B2/3
- C1/3
- D0.5
- E0.25
23The joint distribution for two random variables X and Y is given by . Find the E[X].
- A0.25
- B0.75
- C0.5
- D0.95
- ENone of these
24The joint distribution for two random variables X and Y is given by. Find the marginal density function for Y.
- A3x²
- B6y
- C2y
- D2y²-1
- Ey+6
25The joint distribution for two random variables X and Y is given by . Find the marginal density function for X.
- A6y
- B6y²
- C6x²
- D3x²
- E3x³
26Random variable X has the following PDF f(x) = 3x² / 2, -1 ≤ x ≤ 1. Find E[1/X]
- A4
- B0
- C2
- D1
- E-2
27Random variable X has the following PDF f(x) = 3x² / 2, -1 ≤ x ≤ 1. Find Var[X]
- A0
- B1
- C0.6
- D0.8
- E0.4
28Random variable X has the following PDF f(x) = 3x² / 2, -1 ≤ x ≤ 1. Find E[X]
- A0
- B1
- C2
- D3
- E4
29Random variable X has the following PDF f(x) = 3x² / 2, -1 ≤ x ≤ 1. Find P(-0.8 ≤ X ≤ 0.8)
- A0.31
- B0.428
- C0.512
- D0
- E0.78
30Let Y=2X-3. Find P(Y≥4).
- A0.3438
- B0.53125
- C0.0625
- D0.1563
- E0
31Then find P(Y>0.5).
- A0.5
- B0.25
- C0.75
- D1
- E1.5
32A basketball player makes 90% of her free throws. What is the probability that she will miss for the first time on the seventh shot?
- A0.0001
- B0.053
- C0.002
- D0.001
- E0.01
33If two random variables X and Y have the joint density function, , find the probability P(X+Y<1).
- A1/24
- B1/12
- C5/12
- D1/4
- E0.003
34Let f(x, y) = x + y, 0 ≤ x ≤ 1, 0 ≤ y ≤ 1, be the joint p.d.f. of X and Y. Find the marginal PDF of X.
- Ax
- Bx + 1/2
- Cy + 1/2
- Dx² + 1
- Ex² + y²
35At a university, 14% of students take math and computer classes, and 67% take math class. What is the probability that a student takes computer class given that the student takes math class?
- A0.81
- B0.21
- C0.53
- DNone
- E0.96
36Given that Z is a standard normal random variable. What is the value of Z if the area to the left of Z is 0.9382?
- A1.8
- B1.54
- C2.1
- D1.77
- E3
37208. successful trials, if their total number is 10.
- A6
- B7
- C8
- D5
- E10
38Four independent shots are made to the target. Probability of missing in the first shot is 0.5; in the second shot – 0.3; in the 3rd – 0.2; in the 4th – 0.1. What is the probability that the target is not hit.
- A1.1
- B0.03
- C0.275
- D0.003
- E1.01
39An urn contains 1 white and 9 black balls. Three balls are drawn from the urn without replacement. What is the probability that at least one of the balls is white?
- A0.7
- B0.3
- C0.4
- D0.2
- E0.6
40Probability that each shot hits a target is 0.9. Total number of shots produced to the target is 5. What is the probability that at least one shot hits the target?
- A1-0,9^5
- B0,9^5
- C1-0.1^5
- D0.1^5
- E1-5*0.1
41A coin is tossed twice. Event A={ Head appears in the first tossing}, event B={at least one Tail appears}. Find the conditional probability P(B|A).
- A1/4
- B1/2
- C1/3
- D2/3
- E3/4
42A coin is tossed twice. Event A={ at least one Head appears}, event B={at least one Tail appears}. Find the conditional probability P(B|A).
- A2/3
- B1/3
- C1/2
- D3/4
- E0
43Urn I contains 4 black and 6 white balls, whereas urn II contains 3 white and 7 black balls. An urn is selected at random and a ball is drawn at random from the selected urn. What is the probability that the ball is white?
- A0.45
- B0.15
- C0.4
- D0.9
- E1
44Consider two boxes, one containing 3 white and 7 black balls and the other – 1 white and 9 black balls. A box is selected at random, and a ball is drawn at random from the selected box. What is the probability that the ball selected is black?
- A0.8
- B0.2
- C0.4
- D1.6
- E0.9
45Each of two boxes contains 6 white and 4 black balls. A ball is drawn from 1st box and it is replaced to the 2nd box. Then a ball is drawn from the 2nd box. What is the probability that this ball occurs to be white?
- A0.3
- B0.4
- C0.5
- D0.6
- E0.8
46Consider two boxes, one containing 4 white and 6 black balls and the other - 8 white and 2 black balls. A box is selected at random, and a ball is drawn at random from the selected box. If the ball occurs to be white, what is the probability that the first box was selected?
- A0.4
- B0.6
- C0.8
- D1/3
- E2/3
47A man is made 10 shots on the target. Assume that the probability of hitting the target in one shot is 0,7. What is the most probable number of hits?
- A8
- B7
- C6
- D5
- E9
48PMF of discrete random variable X is given by
Х 0 5 x3
Р 0,6 0,1 0,3
If E[X]=3.5 then find the value of x3.- A10
- B6
- C8
- D12
- E24
49PMF of discrete random variable X is given by
Х -1 5
Р 0,4 0,6
Find variance of X.- A15.4
- B8.64
- C2.6
- D2.93
- E3.33
50PMF of discrete random variable X is given by
Х -1 5
Р 0,4 0,6
Find standard deviation of X.- A15.4
- B8.64
- C2.6
- D2.9393
- E3.3333
51193. PMF of discrete random variable is given by
Х 0 2 4
Р 0,3 0,1 0,6
Find F(2).- A0.4
- B0.6
- C0.3
- D0.7
- E0.1
52PMF of discrete random variable is given by
Х 0 2 4
Р 0,1 0,5 0,4
Find the value of CDF of X in the interval (2, 4].- A0.4
- B0.5
- C0.6
- D0.2
- E1
53What is the probability P{1.3<X≤2.3}?
CDF of discrete random variable X is given by
- A0.8
- B0.2
- C0
- D0.6
- E0.4
54Continuous random variable X is given in the interval [0, 100]. What is the probability P(X=50)?
- A0
- B1
- C0.5
- D0.75
- E0.25
55What is the PDF of X in the interval 1<X≤2? Continuous random variable X has the following CDF:
- A1/2
- B0
- C1
- Dx²/4
- Ex
56Indicate the function that can be PDF of some random variable.
- A1
- B2
- C3
- D4
- E5
- A1
57Indicate the function that can be CDF of some random variable.
- A1
- B2
- C3
- D4
- ENone of these
- A1
58Random variable X is given by density function f(x) = 2x in the interval (0, 1) and otherwise is 0. What is the probability P(0 < X < 1/2) ?
- A1/2
- B1/4
- C0
- D1/8
- ENone of these
59Random variable X is given by density function f(x) = 2x in the interval (0, 1) and otherwise is 0. What is the expectation of X?
- A1/2
- B1
- C4/3
- D2/3
- E0
60Random variable X is given by density function f(x) = x/2 in the interval (0, 2) and otherwise is 0. What is the expectation of X?
- A1/2
- B1
- C4/3
- D2/3
- E0
61Random variable X is uniformly distributed in interval [-11, 20]. What is the probability P(X ≤ 0) ?
- A11/32
- B5/16
- C10/31
- D11/31
- E0
62Random variable X is uniformly distributed in interval [1, 3]. What is the distribution of the random variable Y=3X+1?
- AY is normally distributed in the interval [3, 9]
- BY is uniformly distributed in the interval [4, 10]
- CY is normally distributed in the interval [4, 10]
- DY is exponentially distributed in the interval [4, 10]
- EY has other type of distribution
63Random variable X is uniformly distributed in interval [-11, 26]. What is the probability P(X> - 4)?
- A29/38
- B29/37
- C30/37
- D15/19
- E0
64Random variable X is uniformly distributed in interval [-2, 1]. What is the distribution of the random variable Y=2X+2?
- AY is normally distributed in the interval [-4, 2]
- BY is uniformly distributed in the interval [-2, 4]
- CY is normally distributed in the interval [-2, 4]
- DY is exponentially distributed in the interval [-4, 2]
- EY has other type of distribution
65Random variable X is uniformly distributed in interval [0, 15]. What is the expectation of X?
- A15
- B3.75
- C7.5
- D30
- E0
66Random variable X is uniformly distributed in interval [0, 3]. What is the variance of X?
- A0.75
- B1.5
- C3
- D0.25
- E1
67Normally distributed random variable X is given by density. Find the mean.
- A-1/2
- B1/2
- C1/4
- D0
- E1
68Expectation and standard deviation of the normally distributed random variable X are respectively equal to 15 and 5. What is the probability that in the result of an experiment X takes on the value in interval (5, 20)?
- AФ(20) – Ф(5)
- BФ(1) - Ф(0)
- CФ(20) + Ф(5)
- DФ(1) + Ф(2) - 1
- EФ(2) - Ф(1)
69Random variable X is uniformly distributed on the interval [-2, 2]. Indicate the right values for E[X] and Var(X).
- AE[X]=0 and Var(X)=4
- BE[X]=0 and Var(X)=1.33
- CE[X]=0.5 and Var(X)=1.33
- DE[X]=0 and Var(X)=0
- ENone
70Continuous random variable X is normally distributed with mean=1 and variance=4. Find P(4≤x≤6).
- A0.0606
- B0.202
- C0.0305
- D0.0484
- E0.0822
71A coin tossed twice. What is the probability that head appears in the both tosses.
- A1/2
- B1/4
- C0
- D4/1
- E1
72In each of the 20 independent trials the probability of success is 0.2. Find the variance of the number of successes in these trials.
- A0
- B1
- C10
- D3.2
- E0.32
73Find the probability P(1.7<X<1.9).
The cdf of a random variable X is given by
- A0.16
- B0.8
- C1
- D0.4
- E0.6
74The event A occurs in each of the independent trials with probability p. Find probability that event A occurs at least once in the 5 trials.
- Ap^5
- B1 - (1 - p)^5
- C(1 - p)^5
- D1 - p^5
- ENone
75Probability density function of the normal random variable X is given by: What is the standard deviation?
- A5
- B3
- C25
- D50
- E9
76Three dice are rolled. What is the probability that the points appeared are distinct.
- A1
- B5/9
- C2
- D1/3
- E1/2
77Suppose that the random variable T has the following probability distribution:
t | 0 1 2
P(T = t) | .5 .3 .2 Compute the mean of the random variable T.- A0.8
- B0.5
- C0.7
- D0.1
- E1
78163. Suppose that the random variable T has the following probability distribution:
t | 0 1 2 P(T = t) | .5 .3 .2 Find P{T ≥ 0 and T < 2}- A0.8
- B0.5
- C0.3
- D0.2
- E0.1
79Four persons are to be selected from a group of 12 people, 7 of whom are women. What is the probability that three of those selected are women?
- A0.35
- B0.65
- C0.45
- D0.25
- E0.1211
80The pdf of a random variable X is given by: Calculate the parameter γ.
- A0
- B4
- C1.5
- D2
- E3.5
81We are given the pmf of two random variables X and Y shown in the tables below.
Х 1 3 У 2 4
px 0,4 0,6 py 0,2 0,8
Find E[X+Y].- A5.8
- B2.2
- C2
- D8.8
- E10
82Let X be a continuous random variable with PDF f(x) = cx (0 ≤ x ≤ 1), where c is a constant. Find the value of constant c.
- A1
- B2
- C1/2
- D3/2
- E4
83If the variance of a random variable X is equal to 3, then Var(3X) is :
- A12
- B6
- C3
- D27
- E9
84A class contains 8 boys and 7 girls. The teacher selects 3 of the children at random and without replacement. Calculate the probability that the number of boys selected exceeds the number of girls selected.
- A512/3375
- B28/65
- C8/15
- D1856/3375
- E36/65
85Suppose that P(A|B)=3/5, P(B)=2/7, and P(A)=1/4. Determine P(B|A).
- A24/75
- B24/35
- C6/35
- D12/75
- ENone
86If P(A)=1/2 and P(B)=1/2 then P(A ∩ B)=
- A1/4, always
- B1/4, if A and B are independent
- C1/2, always
- D1/2, if A and B are independent
- ENone
87A box contains 5 red and 4 white marbles. Two marbles are drawn successively from the box without replacement and it is noted that the second one is white. What is the probability that the first is also white?
- A1/3
- B3/8
- C5/8
- D1/8
- E1
88Consider the universal set U and two events A and B such that A ∩ B = Ø and A ∪ B = U. We know that P(A)=1/3. Find P(B).
- A2/3
- B1/3
- C4/9
- DCannot be determined
- E1
89Which of the following statements is always true for A and A^C ?
- AP(AA^c)=1
- BP(A^c)=P(A)
- CP(A+A^c)=0
- DP(AA^c)=0
- ENone
90Table shows the cumulative distribution function of a random variable X. Determine P (X > 4)
X 1 2 3 4
F(X) 1/8 3/8 3/4 1- A1/8
- B1
- C1/2
- D3/4
- E0
91Table shows the cumulative distribution function of a random variable X. Determine P (X ≥ 2)
X 1 2 3 4
F(X) 1/8 3/8 3/4 1- A1/8
- B7/8
- C1/2
- D3/4
- E1/3
92The number of clients arriving each hour at a given branch of a bank asking for a given service follows a Poisson distribution with parameter λ=3. It is assumed that arrivals at different hours are independent from each other. The probability that in a given hour at most 2 clients arrive at this specific branch of the bank is:
- A0.64726
- B0.81521
- C0.42319
- D0.18478
- E0.08391
93In the first step, Joe draws a hand of 5 cards from a deck of 52 cards. What is the probability that Joe has exactly one ace?
- A0.2995
- B0.699
- C0.23336
- D1/4
- E0.4999
94What quantity is given by the formula?
- ACovariance of the random variables X and Y
- BCorrelation coefficient
- CCoefficient of symmetry
- DConditional expectation
- ENone of the given answers is correct
95The pdf of a random variable X is given by .
What are the values of µ and σ?
- Aµ = 1, σ = 4
- Bµ = -1, σ = 4
- Cµ = -1, σ = 2
- Dµ = 1, σ = 8
- Eµ = 1, σ = 2
96Let A, B and C be independent events such that P(A) = 0.5, P(B) = 0.6 and P(C) = 0.1. Calculate P(A^c ∪ B^c ∪ C)
- A0.69
- B0.71
- C0.73
- D0.98
- E1
97The probability that a particular machine breaks down on any day is 0.2 and is independent of the breakdowns on any other day. The machine can break down only once per day. Calculate the probability that the machine breaks down two or more times in ten days.
- A0.0175
- B0.0400
- C0.2684
- D0.6242
- E0.9596
98One card is randomly selected from a shuffled deck of 52 cards and then a die is rolled. Find the probability of obtaining an Ace and rolling an odd number.
- A1/104
- B7/13
- C1/39
- D1/26
- E1/36
99What is the probability of drawing a diamond from a standard deck of 52 cards?
- A1/52
- B13/39
- C1/13
- D1/4
- E1/2
100A regular deck of 52 cards contains 4 different suits (Spades, Hearts, Diamonds, and Clubs) that each have 13 cards. If you randomly choose two cards from the deck, what is the probability that both cards will all be hearts?
- A4/17
- B1/17
- C2/17
- D1/4
- E33/68
101Two fair dice, one red and one blue, each have numbers 1-6. If a roll of the two dice totals 6, what is the probability that the red die is showing a 5?
- A1/6
- B1/5
- C1/3
- D5/6
- E1/18
102The compact disk Jane bought had 12 songs. The first four were rock music. Tracks number 5 through 12 were ballads. She selected the random function in her CD Player. What is the probability of first listening to a ballad?
- A1/3
- B2/3
- C1/2
- D1/6
- E1/12
103Johnson taught a music class for 25 students under the age of ten. He randomly chose one of them. What was the probability that the student was under twelve?
- A1
- B0.5
- C1/25
- D0
- E0.25
104Which of the following is the appropriate definition for the union of two events A and B?
- AThe set of all possible outcomes.
- BThe set of all basic outcomes contained within both A and B.
- CThe set of all basic outcomes in either A or B, or both.
- DNone of the given answers
- EThe set of all basic outcomes that are not in A and B.
105Which of the following is an example of a discrete random variable?
- AThe distance you can drive in a car with a full tank of gas.
- BThe weight of a package at the post office.
- CThe amount of rain that falls over a 24-hour period.
- DThe number of cows on a cattle ranch.
- EThe time that a train arrives at a specified stop.
106A probability function is a rule of correspondence or equation that:
- AFinds the mean value of the random variable.
- BAssigns values of x to the events of a probability experiment.
- CAssigns probablities to the various values of x.
- DDefines the variability in the experiment.
- ENone of the given answers is correct.
107Suppose that the random variable T has the following probability distribution:
t | 0 1 2 P(T = t) | .5 .3 .2
Find P{t ≤ 0)- A0.8
- B0.5
- C0.3
- D0.2
- E0.1
108Twenty percent of the paintings in a gallery are not originals. A collector buys a painting. He has probability 0.10 of buying a fake for an original but never rejects an original as a fake, What is the (conditional) probability the painting he purchases is an original?
- A1/41
- B40/41
- C80/41
- D1
- E40/100
109Four persons are to be selected from a group of 12 people, 7 of whom are women. What is the probability that the first and third selected are women?
- A0.3182
- B0.5817
- C0.78
- D0.916
- E0.1211
110In a certain town, 50% of the households own a cellular phone, 40% own a pager, and 20% own both a cellular phone and a pager. The proportion of households that own neither a cellular phone nor a pager is
- A90%
- B70%
- C10%
- D30%.
- E25%
111Which of these has a Geometric model?
- Athe number of aces in a five-card Poker hand
- Bthe number of people we survey until we find two people who have taken Statistics
- Cthe number of people in a class of 25 who have taken Statistics
- Dthe number of people we survey until we find someone who has taken Statistics
- Ethe number of sodas students drink per day
112Suppose a computer chip manufacturer rejects 15% of the chips produced because they fail presale testing. If you test 4 chips, what is the probability that not all of the chips fail?
- A0.9995
- B5.06 × 10-4
- C0.15
- D0.6
- E0.5220
113Suppose that 10% of people are left handed. If 8 people are selected at random, what is the probability that exactly 2 of them are left handed?
- A0.0331
- B0.0053
- C0.1488
- D0.0100
- E0.2976
114A student can solve 6 from a list of 10 problems. For an exam 8 questions are selected at random from the list. What is the probability that the student will solve exactly five problems?
- A0.282
- B0.02
- C0.376
- D0.133
- ENone
115Twelve items are independently sampled from a production line. If the probability any given item is defective is 0.1, the probability of at most two defectives in the sample is closest to
- A0.3874
- B0.9872
- C0.7361
- D0.8891
- ENone
116A company which produces a particular drug has two factories, A and B. 30% of the drug are made in factory A, 70% in factory B. Suppose that 95% of the drugs produced by the factory A meet specifications while only 75% of the drugs produced by the factory B meet specifications. If I buy the drug, what is the probability that it meets specifications?
- A0.95
- B0.81
- C0.75
- D0.7
- E0.995
117A class consists of 490 female and 510 male students. The students are divided according to their marks Passed and Did not pass
Passed Did not pass
Female 430 60
Male 410 100
If one person is selected randomly, what is the probability that it did not pass given that it is male.- A0.066
- B0.124
- C0.414
- D0.812
- E0.196
118A smoke-detector system consists of two parts A and B. If smoke occurs then the item A detects it with probability 0.95, the item B detects it with probability 0.98 whereas both of them detect it with probability 0.94. What is the probability that the smoke will not be detected?
- A0.01
- B0.99
- C0.04
- D0.96
- ENone
119Two events each have probability 0.2 of occurring and are independent. The probability that neither occur is
- A0.64
- B0.04
- C0.2
- D0.4
- ENone
120Which of the following random variables would you expect to be discrete?
- AThe weights of mechanically produced items
- BThe number of children at a birthday party
- CThe lifetimes of electronic devices
- DThe length of time between emergency arrivals at a hospital
- EThe times, in seconds, for a 100m sprint
121Which of the following is not a property of a binomial experiment?
- Athe experiment consists of a sequence of n identical trials
- Beach outcome can be referred to as a success or a failure
- Cthe probabilities of the two outcomes can change from one trial to the next
- Dthe trials are independent
- Ebinomial random variable can be approximated by the Poisson
122Given a normal distribution with µ=100 and σ=10, what is the probability that X>75?
- A0.99
- B0.25
- C0.49
- D0.45
- E0
123A set of possible values that a random variable can assume and their associated probabilities of occurrence are referred to as
- AProbability distribution
- BThe expected value
- CThe standard deviation
- DCoefficient of variation
- ECorrelation
124A medical treatment has a success rate of 0.8. Two patients will be treated with this treatment. Assuming the results are independent for the two patients, what is the probability that neither one of them will be successfully cured?
- A0.5
- B0.36
- C0.2
- D0.04
- E0.4
125The probability is p = 0.80 that a patient with a certain disease will be successfully treated with a new medical treatment. Suppose that the treatment is used on 40 patients. What is the "expected value" of the number of patients who are successfully treated?
- A40
- B20
- C8
- D32
- E124
126Heights of college women have a distribution that can be approximated by a normal curve with a mean of 65 inches and a standard deviation equal to 3 inches. About what proportion of college women are between 65 and 67 inches tall?
- A0.75
- B0.5
- C0.25
- D0.17
- E0.85
127Which one of these variables is a continuous random variable?
- AThe time it takes a randomly selected student to complete an exam.
- BThe number of tattoos a randomly selected person has.
- CThe number of women taller than 68 inches in a random sample of 5 women.
- DThe number of correct guesses on a multiple choice test.
- EThe number of 1’s in N rolls of a fair die
128A random variable X has a probability distribution as follows:
X | 0 1 2 3
P(X) | 2k 3k 13k 2k
Then the probability that P(X < 2.0) is equal to- A0.90
- B0.25
- C0.65
- D0.15
- E1
129110. A random variable Y has the following distribution:
Y | -1 0 1 2
P(Y)| 3C 2C 0.4 0.1
The value of the constant C is:- A0.1
- B0.15
- C0.2
- D0.25
- E0.75
130A movie theater sells 3 sizes of popcorn (small, medium, and large) with 3 choices of toppings (no butter, butter, extra butter). How many possible ways can a bag of popcorn be purchased?
- A1
- B3
- C9
- D27
- E62
131A fair coin is thrown in the air four times. If the coin lands with the head up on the first three tosses, what is the probability that the coin will land with the head up on the fourth toss?
- A0
- B1/16
- C1/8
- D1/2
- E1/4
Información
- Descripción
- Test sobre Sin título, creado por Madi Zhaksigeldi el 22/05/2022.
- Autor
- Madi Zhaksigeldi
- Idioma
- English
- Visitas
- 12
- Valoración
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