Deck 6: Probability.

Question 1

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

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

Answer 1

0.6915

Question 2

A class consists of 10 male and 30 female students.If one student is randomly selected from the class,what is the probability of selecting a male student?

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

Answer 2

10/40

Question 3

What proportion of a normal distribution is located between z = 0 and z = +1.50?

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

Answer 3

0.4332

Question 4

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 5

Which of the following accurately describes the proportions in the body of a normal distribution?

A)Body proportions on the right side of the z-score are greater than 0.50; on the left side, they are less than 0.50.
B)Body proportions on the right side of the z-score are less than 0.50; on the left side, they are greater than 0.50.
C)Body proportions on either side of the z-score are less than 0.50.
D)Body proportions on either side of the z-score are greater than 0.50.

Question 6

Which of the following accurately describes the proportions in the tails of a normal distribution?

A)Proportions in the right-hand tail are positive, and proportions in the left-hand tail are negative.
B)Proportions in the right-hand tail are negative, and proportions in the left-hand tail are positive.
C)Proportions in both tails are positive.
D)Proportions in both tails are negative.

Question 7

What proportion of a normal distribution is located between z = -1.25 and z = +1.25?

A)0.8944
B)0.2112
C)0.3944
D)0.7888

Question 8

A class consists of 10 male and 30 female students.A random sample of n = 3 students is selected.If the first two students are both females,what is the probability that the third student is a male?

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

Question 9

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

A)0.0808
B)0.4192
C)-0.0808
D)-0.4192

Question 10

Which of the following accurately describes the proportions in the tails of a normal distribution?

A)Proportions in the right-hand tail are greater than 0.50, and proportions in the left-hand tail are less than 0.50.
B)Proportions in the right-hand tail are less than 0.50, and proportions in the left-hand tail are greater than 0.50.
C)Proportions in both tails are less than 0.50.
D)Proportions in both tails are greater than 0.50.

Question 11

Which of the following is a requirement for 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 12

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

Question 13

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

Question 14

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 15

What proportion of a normal distribution is located in the tail beyond z = 1.50?

A)0.9332
B)0.0668
C)0.4332
D)0.1336

Question 16

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 17

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

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

Question 18

A vertical line drawn through a normal distribution at z = -1.00 separates the distribution into two sections,the body and the tail.What proportion of the distribution is in the tail?

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

Question 19

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 20

A vertical line drawn through a normal distribution at z = -1.00 separates the distribution into two sections,the body and the tail.What proportion of the distribution is in the body?

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

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

A normal distribution has a mean of µ = 40 with σ = 10.If a vertical line is drawn through the distribution at X = 55,what proportion of the scores are on the right side of the line?

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

Question 23

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 24

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)0.8413
B)0.1587
C)0.3085
D)0.6915

Question 25

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 be less than X = 84?

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

Question 26

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 27

A normal distribution has μ = 20 and σ = 4.What is the probability of randomly selecting a score greater than 25 from this distribution?

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

Question 28

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 29

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 30

A normal distribution has a mean of µ = 40 with σ = 10.If a vertical line is drawn through the distribution at X = 35,what proportion of the scores are on the left side of the line?

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

Question 31

What z-score value separates the highest 70% of the scores in a normal distribution from the lowest 30%?

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

Question 32

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 = 55?

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

Question 33

A normal distribution has a mean of µ = 40 with σ = 8.If one score is randomly selected from this distribution,what is the probability that the score will be less than X = 34?

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

Question 34

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 35

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 36

A normal distribution has a mean of µ = 60 with σ = 8.If one score is randomly selected from this distribution,what is the probability that the score will be greater than X = 54?

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

Question 37

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 = 100 and X = 130?

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

Question 38

What z-score value separates the highest 10% of the scores in a normal distribution from the lowest 90%?

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

Question 39

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 40

A normal distribution has a mean of µ = 70 with σ = 10.If one score is randomly selected from this distribution,what is the probability that the score will be greater than X = 82?

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

Question 41

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 42

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 43

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 44

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 45

IQ scores form a normal distribution with µ = 100 and σ = 15.Individuals with IQs above 140 are classified in the genius category.What proportion of the population consists of geniuses?

A)0.9962
B)0.5038
C)0.4962
D)0.0038

Question 46

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 47

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 48

IQ scores form a normal distribution with µ = 100 and σ = 15.Individuals with IQs between 90 and110 are classified as average.What proportion of the population is average?

A)0.7486
B)0.5028
C)0.4972
D)0.2486

Question 49

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

Question 50

A vertical line drawn through a normal distribution at z = 1.40 divides the distribution into two sections.The proportion in the smaller section is 0.0808.

Question 51

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

Question 52

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 53

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

Question 54

The proportion in the tail of a normal distribution can never be more than 0.50.

Question 55

The probability of randomly selecting a red marble from a jar that contains 10 red marbles and 20 blue marbles is 1/30.

Question 56

The proportion in the body of a normal distribution can never be less than 0.50.

Question 57

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

Question 58

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 59

The tail is on the right side of a normal distribution for any z-score value greater than zero.

Question 60

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

Question 61

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 62

A vertical line is drawn through a normal distribution so that the proportion in the tail is 0.1841.The line was drawn at z = 0.90 or at z = -0.90.

Question 63

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

Question 64

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 65

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 = 105.

Question 66

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

Question 67

The middle 90% of a normal distribution is located between z = -1.96 and z = 1.96

Question 68

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

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.

Question 70

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 = 130 is p = 0.9987.

Question 71

For a normal distribution,the proportion in the tail beyond z = 0.30 is p = 0.1179.

Question 72

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

Question 73

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 74

For a normal distribution with µ = 50 and σ = 10,the line separating the highest 10% of the scores from the rest is located at X = 51.28.

Question 75

A vertical line drawn through a normal distribution at z = -0.50 separates the distribution into two sections.The proportion in the larger section is 0.6915.

Question 76

For any normal distribution,the probability of randomly selecting a z-score less than z = 1.40 is p = 0.9192.

Question 77

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 78

A vertical line is drawn through a normal distribution so that 47.5% of the distribution is located between the line and the mean.The line is drawn at z = 1.96 or at z = -1.96.

Question 79

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

Question 80

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