Deck 6: Probability

Question 1

What proportion of a normal distribution is located between the mean and z = 1.40?

A)0.9192
B)0.0808
C)0.4192
D)0.8384

Answer 1

C

Question 2

What proportion of a normal distribution is located between z = -0.25 and z = +0.25?

A)0.5987
B)0.4013
C)0.0987
D)0.1974

Answer 2

D

Question 3

What proportion of a normal distribution is located between z = -1.50 and z = +1.50?

A)0.9332
B)0.0668
C)0.4332
D)0.8664

Answer 3

D

Question 4

A normal distribution has a mean of µ = 40 with σ = 10.What proportion of the scores in this distribution are smaller than X = 35?

A)0.3085
B)0.6915
C)0.0668
D)0.9332

Question 5

A jar contains 10 red marbles and 30 blue marbles.What is the probability of randomly selecting a red marble from the jar?

A)10/30
B)10/40
C)1/10
D)1/40

Question 6

A vertical line is drawn through a normal distribution at z = 1.20.What proportion of the distribution is on the left-hand side of the line?

A)0.8849
B)0.1151
C)0.3849
D)0.7698

Question 7

A jar contains 10 red marbles and 30 blue marbles.A random sample of n = 3 marbles is selected from the jar.If the first two marbles are both blue, what is the probability that the third marble will be red?

A)10/37
B)10/38
C)10/40
D)8/38

Question 8

What is the probability of randomly selecting a z-score less than z = 1.25 from a normal distribution.

A)0.8944
B)0.1056
C)0.3944
D)0.2112

Question 9

What z-score values form the boundaries for the middle 60% of a normal distribution?

A)z = +0.25 and z = -0.25
B)z = +0.39 and z = -0.39
C)z = +0.52 and z = -0.52
D)z = +0.84 and z = -0.84

Question 10

What is the probability of randomly selecting a z-score greater than z = 0.75 from a normal distribution.

A)0.7734
B)0.2266
C)0.2734
D)0.4532

Question 11

What proportion of a normal distribution is located between the mean and z = -0.40?

A)0.6554
B)0.3446
C)0.1554
D)0.3108

Question 12

Which of the following are requirements of a random sample?

A)every individual has an equal chance of being selected
B)the probabilities cannot change during a series of selections
C)there must be sampling with replacement
D)All of the other 3 choices are correct.

Question 13

What proportion of a normal distribution is located in the tail beyond z = 2.00?

A)0.9772
B)0.0228
C)0.4772
D)0.0456

Question 14

What z-score value separates the top 70% of a normal distribution from the bottom 30%?

A)z = 0.52
B)z = 0.84
C)z = -0.52
D)z = -0.84

Question 15

What z-score value separates the top 10% of a normal distribution from the bottom 90%?

A)z = 1.28
B)z = 0.25
C)z = -1.28
D)z = -0.25

Question 16

A vertical line is drawn through a normal distribution at z = 0.50, and separates the distribution into two sections.What proportion of the distribution is in the larger section?

A)0.6915
B)0.3085
C)0.1915
D)0.3830

Question 17

What proportion of a normal distribution is located in the tail beyond z = -1.00?

A)0.8413
B)0.1587
C)-0.3413
D)-0.1587

Question 18

A vertical line is drawn through a normal distribution at z = 0.80.What proportion of the distribution is on the right-hand side of the line?

A)0.7881
B)0.2119
C)0.2881
D)0.5762

Question 19

A normal distribution has a mean of µ = 40 with σ = 10.What proportion of the scores in this distribution are greater than X = 55?

A)0.3085
B)0.6915
C)0.0668
D)0.9332

Question 20

A normal distribution has μ = 80 and σ = 10.What is the probability of randomly selecting a score greater than 90 from this distribution?

A)p = 0.8413
B)p = 0.1587
C)p = 0.3085
D)p = 0.6915

Question 21

A normal distribution has a mean of µ = 100 with σ = 20.If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 80 and X = 100?

A)0.8413
B)0.1587
C)0.3413
D)0.6826

Question 22

Under what circumstances does the binomial distribution approximate a normal distribution?

A)when pn > 10
B)when qn > 10
C)when pn and qn are both > 10
D)when npq > 10

Question 23

A true/false test has 100 questions.Using the normal approximation to the binomial distribution, what is the probability of getting 55 or more correct by just guessing?

A)p(X > 55)
B)p(X > 55.5)
C)p(X > 54.5)
D)none of the above

Question 24

A normal distribution has a mean of µ = 80 with σ = 20.What score separates the highest 40% of the distribution from the rest of the scores?

A)X = 75
B)X = 85
C)X = 54.4
D)X = 105.6

Question 25

A normal distribution has a mean of µ = 80 with σ = 20.What score separates the lowest 30% of the distribution from the rest of the scores?

A)X = 90.4
B)X = 69.6
C)X = 110
D)X = 50

Question 26

Scores on the SAT form a normal distribution with a mean of µ = 500 with σ = 100.If the state college only accepts students who score in the top 60% on the SAT, what is the minimum score needed to be accepted?

A)X = 475
B)X = 525
C)X = 440
D)X = 560

Question 27

A normal distribution has a mean of µ = 70 with σ = 12.If one score is randomly selected from this distribution, what is the probability that the score will be greater than X = 58?

A)0.8413
B)0.1577
C)0.3413
D)0.6826

Question 28

A binomial distribution has p = 1/5 and q = 4/5 with n = 100.In the normal approximation to this distribution what is the z -score corresponding to X = 25?

A)z = 0.50
B)z = 1.00
C)z = 1.25
D)z = 1.50

Question 29

A normal distribution has a mean of µ = 100 with σ = 20.If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 90 and X = 120?

A)0.1498
B)0.4672
C)0.5328
D)0.2996

Question 30

A normal distribution has a mean of µ = 100 with σ = 20.If one score is randomly selected from this distribution, what is the probability that the score will have a value between X = 90 and X = 110?

A)0.6915
B)0.3085
C)0.1915
D)0.3830

Question 31

A normal distribution has a mean of µ = 80 with σ = 20.What score separates the highest 15% of the distribution from the rest of the scores?

A)X = 59.2
B)X = 100.8
C)X = 95
D)X = 65

Question 32

A normal distribution has a mean of µ = 24 with σ = 3.What is the minimum score needed to be in the top 14% of the distribution?

A)X = 20.76
B)X = 27.24
C)X = 25.08
D)X = 24.42

Question 33

A normal distribution has a mean of µ = 70 with σ = 12.If one score is randomly selected from this distribution, what is the probability that the score will be less than X = 55?

A)0.3944
B)0.1056
C)0.8944
D)0.7888

Question 34

A normal distribution has a mean of µ = 70 with σ = 12.If one score is randomly selected from this distribution, what is the probability that the score will be less than X = 76?

A)0.1915
B)0.3085
C)0.6915
D)0.3830

Question 35

A true/false test has 100 questions.Using the normal approximation to the binomial distribution, what is the probability of getting more than 55 correct by just guessing?

A)p(X > 55)
B)p(X > 55.5)
C)p(X > 54.5)
D)none of the above

Question 36

A normal distribution has a mean of µ = 70 with σ = 12.If one score is randomly selected from this distribution, what is the probability that the score will be greater than X = 79?

A)0.7734
B)0.2266
C)0.2734
D)0.3085

Question 37

John drives to work each morning and the trip takes an average of µ = 38 minutes.The distribution of driving times is approximately normal with a standard deviation of σ = 5 minutes.For a randomly selected morning, what is the probability that John's drive to work will take between 36 and 40 minutes?

A)0.0793
B)0.1526
C)0.1554
D)0.3108

Question 38

A multiple-choice test with 48 questions has four choices for each question.What is the probability of getting more than 12 questions correct by just guessing?

A)0.5000
B)0.4325
C)0.5675
D)0.0675

Question 39

For a binomial distribution with p = q = ½ and n = 36, what is the mean for the normal approximation?

A)3
B)9
C)16
D)18

Question 40

John drives to work each morning and the trip takes an average of µ = 38 minutes.The distribution of driving times is approximately normal with a standard deviation of σ = 5 minutes.For a randomly selected morning, what is the probability that John's drive to work will take less than 35 minutes?

A)0.6554
B)0.3446
C)0.7257
D)0.2743

Question 41

For a normal distribution, proportions in the right-hand tail are positive and proportions in the left-hand tail are negative.

Question 42

For any normal distribution, the proportion located between the mean and z = 1.40 is 0.9192.

Question 43

A vertical line drawn through a normal distribution at z = -0.80 will separate the distribution into two sections.The proportion in the larger section is 7881.

Question 44

If one score is randomly selected from a normal distribution with µ = 100 and σ = 20, the probability of obtaining a score less than X = 95 is p = 0.4013.

Question 45

A vertical line is drawn through a normal distribution dividing the distribution into two parts.If the smaller part equals 0.1915 of the distribution, then the line was drawn at z = 0.50 or at z = -0.50.

Question 46

If one score is randomly selected from a normal distribution with µ = 100 and σ = 20, the probability of obtaining a score greater than X = 110 is p = 0.6915.

Question 47

A jar contains 10 red marbles and 20 blue marbles.If you take a random sample of two marbles from this jar and the first marble is blue, then the probability that the second marble is blue is p = 19/29.

Question 48

For a normal distribution, the z-score boundary that separates the lowest 2.5% of the scores from the rest is z = -1.96.

Question 49

A vertical line drawn through a normal distribution at z = 1.25 will separate the distribution into two sections.The proportion in the smaller section is 0.1056.

Question 50

For any normal distribution, exactly 97.50% of the z-score values are less than z = 1.96.

Question 51

For a normal distribution with µ = 100 and σ = 20, the score that separates the top 60% of the distribution from the bottom 40% is X = 95.

Question 52

When the z-score value in a normal distribution is negative, the body is on the right-hand side of the distribution.

Question 53

For a normal distribution, the proportion in the tail beyond z = 1.50 is p = 0.0668.

Question 54

For a normal distribution, the proportion in the tail beyond z = -2.00 is equal to 0.0228.

Question 55

For any normal distribution, the proportion in the tail beyond z = 2.00 is p = 0.0228.

Question 56

All probabilities can be expressed as decimal values ranging from 0 to 1.00.

Question 57

A vertical line drawn through a normal distribution at z = -0.75 will separate the distribution into two sections.The proportion in the smaller section is 0.2734.

Question 58

For a population with a mean of μ = 80 and σ = 10, only 2.28% of the scores are greater than X = 100.

Question 59

For a normal distribution with µ = 80 and σ = 10 the score that separates the bottom 10% of the distribution from the rest is 67.2

Question 60

For a normal distribution, the proportion located between z = -1.00 and z = +1.00 is
p = 34.13%

Question 61

For a binomial distribution, the probability of obtaining a score greater than 19 is computed as p(X > 19.5).

Question 62

For the normal approximation to the binomial distribution with n = 100 and p = 1/5, the probability of selecting a score greater than or equal to 25 is p = 0.1056.

Question 63

A binomial distribution with p = 2/3 and n = 24, meets the criterion for using the normal approximation.
65 The binomial distribution for p = ¼ and n = 96 has a mean of μ = 24.

Question 64

For a binomial distribution, the probability of obtaining a score of X = 19 or greater is computed as p(X > 18.5).

Question 65

The binomial distribution for p = ½ and n = 100 has a standard deviation of σ = 25.

Question 66

If one score is randomly selected from a normal distribution with µ = 100 and σ = 20, the probability of obtaining a score between X = 90 and X = 100 is p = 0.3085.

Question 67

For the normal approximation to the binomial distribution with n = 100 and p = ½ , a score of X = 60 corresponds to a z-score of z = 2.00.

Question 68

If one score is randomly selected from a normal distribution with µ = 100 and σ = 20, the probability of obtaining a score less than X = 70 is p = 0.0013.

Question 69

If one score is randomly selected from a normal distribution with µ = 100 and σ = 20, the probability of obtaining a score between X = 80 and X = 120 is p = 0.3413.