Deck 8: Are Your Curves Normal Probability and Why It Counts

Question 1

What is true of z scores that are equal to the mean?

A)They are negative.
B)They are positive.
C)They are equal to zero.
D)They are equal to one.

Answer 1

C

Question 2

What types of values are most likely to be seen?

A)Values very close to the mean
B)Values very far from the mean
C)Very high values
D)Very low values

Answer 2

A

Question 3

Under the normal curve, approximately what percentage of scores falls between −1 and +1 standard deviations around the mean?

A)14%
B)34%
C)68%
D)95%

Answer 3

C

Question 4

What percentage of all scores fall above a z score of +1?

A)16%
B)34%
C)50%
D)84%

Question 5

Which of the following is a characteristic of the normal curve?

A)Mean, median, and mode are different.
B)Mean, median, and mode are the same.
C)Mean and median are the same, but the mode is different.
D)Mean and mode are the same, but the median is different.

Question 6

What type of standard score has M = 0 and SD = 1?

A)IQ score
B)T score
C)x score
D)z score

Question 7

When we want to infer from a sample to the population, what assumption must be met?

A)The sample is normally distributed.
B)The sample is large.
C)The population is normally distributed.
D)The population is large.

Question 8

Which of the following characteristics is associated with the "tails" of the normal curve?

A)asymptotic
B)symmetry
C)probability
D)bell-shape

Question 9

If you fold a normal curve, each half would fit perfectly on top of the other.This characteristic is known as _______.

A)asymptotic
B)symmetry
C)probability
D)variability

Question 10

If you want to calculate a z score for a test where your raw score was 24, what other information must you know?

A)shape of the distribution
B)mean, median, and mode
C)mean and standard deviation
D)standard deviation only

Question 11

Under the normal curve, approximately what percentage of scores falls between −1 and −2 standard deviations below the mean?

A)14%
B)34%
C)68%
D)95%

Question 12

Which of the following is true of z scores that fall below the mean?

A)They are positive.
B)They are equal to the mode.
C)They are negative.
D)They are in the upper half of the distribution.

Question 13

The fact that the tails of a normal distribution never touch the horizontal axis relates to the following property: ______.

A)symmetrical
B)asymptotic
C)equidistant
D)approximate

Question 14

What is the basis for the normal curve?

A)mean
B)asymptotic
C)probability
D)symmetry

Question 15

What percentage of all scores fall below a z score of +1?

A)16%
B)34%
C)50%
D)84%

Question 16

Which of the following is another name for the normal curve?

A)asymptotic
B)symmetry
C)probability
D)bell-shaped curve

Question 17

What characteristic of the normal curve deals with skewness?

A)asymptotic
B)symmetry
C)probability
D)mean, median, and mode

Question 18

What is the foundation of inferential statistics?

A)probability
B)linear algebra
C)mathematical proofs
D)Algebra

Question 19

If you know the z score, standard deviation(s), and mean (M), what formula would you use to compute the raw score (X)?

A)X = (z + s) ÷ M
B)M = z(s) + X
C)X = z(s) + M
D)z = (M - X) ÷ s

Question 20

Which of the following is true of z scores that fall above the mean?

A)They are negative.
B)They are positive.
C)They are equal to zero.
D)They are equal to one.

Question 21

If I flip a coin 10 times, how many possible combinations or outcomes could I have?

A)10²
B)2¹⁰
C)10¹⁰
D)2²

Question 22

_______ of scores fall within three standard deviations of the mean.

A)50%
B)95%
C)68%
D)99.5%

Question 23

What is the t score for a z score of +3?

A)30
B)50
C)80
D)100

Question 24

Under the normal curve, if a z score of 1.65 included 45% of the area above the mean, what percentage would remain above 1.65 on the x-axis?

A)5%
B)25%
C)85%
D)95%

Question 25

If a distribution has a mean of 100 and a standard deviation of 15, what value would be +2 standard deviations from the mean?

A)70
B)85
C)115
D)130

Question 26

The _______ is the most commonly used standard score.

A)z score
B)t score
C)f score
D)p score

Question 27

To calculate a z score, you subtract ______.

A)the mean from the raw score and divide this difference by the standard deviation
B)the mean from the raw score and divide this difference by the variance
C)the raw score from the mean and divide this difference by the standard deviation
D)the raw score from the mean and divide this difference by the variance

Question 28

z scores that fall below the mean are _______.

A)positive
B)negative
C)either positive or negative
D)zero

Question 29

If the null hypothesis claims that there is no difference between groups, it assumes the likelihood of this to be _______.

A)0%
B)5%
C)95%
D)100%

Question 30

What type of standard score is computed by multiplying the z score by 10 and adding 50?

A)IQ score
B)t score
C)x score
D)z score

Question 31

A score that is 2.5 standard deviations below the mean would have a z score of _______.

A)2.5
B)−2.5
C)0
D)25

Question 32

What is the z score for a raw score of 85 where the group mean is 75, and the standard deviation is 5?

A)−2.0
B)2.5
C)2.0
D)−2.5

Question 33

In a distribution with a mean of 100 and a standard deviation of 15, what is the probability that a score will be 115 or higher?

A)16%
B)34%
C)50%
D)84%

Question 34

_______ of scores fall within one standard deviation of the mean.

A)99.5%
B)68%
C)50%
D)95%

Question 35

A score that is three standard deviations above the mean would have a z score of _______.

A)0
B)−3
C)3
D)1

Question 36

If a distribution has a mean of 50 and a standard deviation of 5, what value would be −1 standard deviation from the mean?

A)45
B)50
C)55
D)60

Question 37

z scores that fall above the mean are _______.

A)positive
B)negative
C)zero
D)one

Question 38

_______ of scores fall on either side of the distribution.

A)99.5%
B)68%
C)50%
D)95%

Question 39

What is the standard used by statisticians to determine the probability of an event occurring outside of chance alone?

A)0.05%
B)5%
C)95%
D)99%

Question 40

What is the t score for a z score of −1?

A)10
B)40
C)50
D)60

Question 41

What you need to calculate first before calculating the kurtosis?

A)mean and standard deviation
B)median and standard deviation
C)mode and variance
D)median and variance

Question 42

What is the term associated with the lack of symmetry in a distribution?

A)ogive
B)skewness
C)kurtosis
D)variability

Question 43

If a distribution has a mean of 50 and a standard deviation of 25, how many standard deviations is 0 from the mean?

A)2
B)−2
C)0
D)5

Question 44

In order to say that a distribution is positively skewed, which of the following must be true?

A)right tail must be longer than left
B)right tail must be shorter than left
C)right and left tail must be equal
D)curve must be bell shaped

Question 45

The entire normal curve contains _______ of scores.

A)25%
B)50%
C)99.9%
D)100%

Question 46

Both t scores and z scores are considered what type of score?

A)standard scores
B)error scores
C)average scores
D)standardized scores

Question 47

A distribution of scores in which almost the entire class scored very low, but a few students scored fairly high would be ______.

A)positively skewed
B)negatively skewed
C)unskewed
D)normally distributed

Question 48

A distribution of scores in which almost the entire class scored very high, but a few students scored fairly low would be ______.

A)negatively skewed
B)positively skewed
C)unskewed
D)normally distributed

Question 49

If a distribution has a mean of 1,000 and a standard deviation of 100, how many standard deviations is 600 from the mean?

A)−2
B)−4
C)4
D)2

Question 50

In order to say that a distribution is negatively skewed, which of the following must be true?

A)right tail must be longer than the left
B)left tail must be longer than the right
C)both tails must be of equal length
D)the curve must be bell shaped

Question 51

When the left tail of a distribution's curve is longer the right, what is this called?

A)platykurtic
B)leptokurtic
C)positive skew
D)negative skew

Question 52

What is the term associated with how flat or peaked a distribution appears?

A)ogive
B)skewness
C)kurtosis
D)variability

Question 53

What do you need to calculate first before calculating skewness?

A)mean and median
B)median and mode
C)mode and mean
D)mode and variance

Question 54

What two scores would divide a normal distribution such that 64.26% of the general population falls within them if the mean is 100 and the standard deviation is 15?

A)80 to 120
B)85 to 115
C)90 to 110
D)75 to 125

Question 55

Which of the following can be used to measure the shape of a distribution?

A)mean
B)mode
C)kurtosis
D)median

Question 56

The study of probability is the basis for determining the degree of confidence we have in stating that a particular finding or outcome is true.

Question 57

When most people scored high on a test of knitting knowledge, and very few people scored low, what is the distribution called?

A)platykurtic
B)leptokurtic
C)positively skewed
D)negatively skewed

Question 58

If a distribution has a mean of 30 and a standard deviation of 5, how many standard deviations is 60 from the mean?

A)5
B)6
C)−6
D)0

Question 59

Kurtosis is used to ______.

A)measure the central tendency of the distribution
B)describe the shape of the distribution
C)measure the variance in the distribution
D)describe the range of a distribution

Question 60

If a distribution has a mean of 25 and a standard deviation of 2, what value would be −4 standard deviations from the mean?

A)17
B)14
C)25
D)33

Question 61

The percentages or areas under the normal curve can be interpreted as probabilities.

Question 62

Standard scores are raw scores that have been adjusted for the particular mean and standard deviation of the distribution from which they are derived.

Question 63

Rank the order of the following z scores in terms of distance from the mean: +2, −3, −1, +1, and 0.

Question 64

Define asymptotic.

Question 65

What are three characteristics of a normal curve?

Question 66

Are distributions always normal?

Question 67

Events that occur in the extremes of the normal curve have a very small probability of occurring.

Question 68

What is a z score?

Question 69

Algebra allows us to determine the exact mathematical likelihood that a difference between groups is due to practice or treatment, as compared with chance or error.

Question 70

The normal curve is only sometimes symmetrical.

Question 71

Why is it important that the tails of a normal curve never touch the x-axis?

Question 72

What percentage of scores fall between the following z scores: −1 to +1; −1 to +2; and −1 to +3?

Question 73

The normal curve has no skew.

Question 74

Why are there no pluses and minuses on the z score table?

Question 75

Why do we use standard scores?

Question 76

What does a z score of −4 mean?