Deck 8: Probability and Why It Counts: Fun With a Bell-Shaped Curve

Question 1

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%

Answer 1

14%

Question 2

A z score that falls below the mean is ______.

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

Answer 2

negative

Question 3

What type of standard score indicates the number of standard deviations from the mean?

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

Answer 3

z score

Question 4

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%

Question 5

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 6

Which of the following statements is TRUE 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 7

What characteristic of the normal curve deals with skewness?

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

Question 8

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

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

Question 9

The characteristic associated with the "tails" of the normal curve is ______

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

Question 10

What is another name for the normal curve?

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

Question 11

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 0.
D)They are equal to 1.

Question 12

A z score that falls above the mean is ______.

A)negative
B)positive
C)equal to 0
D)equal to 1

Question 13

What is the foundation of inferential statistics?

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

Question 14

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

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

Question 15

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

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

Question 16

What types of values are most likely to be seen in a normal distribution?

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

Question 17

What is the basis for the normal curve?

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

Question 18

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 19

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

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

Question 20

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

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

Question 21

z scores that fall below the mean are ______.

A)positive
B)negative
C)either positive or negative
D)0

Question 22

What percentage of scores fall on either side of the distribution?

A)50%
B)68%
C)34%
D)99.5%

Question 23

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 24

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

A)506%
B)84%
C)16%
D)34%

Question 25

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 26

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

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

Question 27

The percentage of scores that fall within 1 standard deviation of the mean is ______.

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

Question 28

What percentage of scores fall within 3 standard deviations of the mean?

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

Question 29

With a raw score of 85,a group mean of 75,and a standard deviation of 5,what is the z score?

A)-2.0
B)2.5
C)2.0
D)-2.5

Question 30

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 31

The ______ is the most commonly used standard score.

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

Question 32

How is the z score calculated?

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

Question 33

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

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

Question 34

By multiplying the z score by 10 and adding 50,which standard score is computed?

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

Question 35

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 36

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 37

Which of the following is considered an extreme z score indicating a TRUE difference between groups?

A)>50%
B)<5%
C)95%
D)100%

Question 38

A z score of -1 has a T score of ______.

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

Question 39

z scores that fall above the mean are ______.

A)positive
B)negative
C)0
D)1

Question 40

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 41

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

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

Question 42

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 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

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 45

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 46

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 47

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

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

Question 48

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 49

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

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

Question 50

What do 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 51

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 52

The entire normal curve contains ______ of scores.

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

Question 53

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 54

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

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

Question 55

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 56

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)25
B)14
C)17
D)33

Question 57

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 58

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

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

Question 59

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 60

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 61

Why are there no plus or minus signs on the z score table?

Question 62

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

Question 63

What is a z score?

Question 64

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

Question 65

What are three characteristics of a normal curve?

Question 66

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

Question 67

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

Question 68

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 69

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

Question 70

The normal curve has no skew.

Question 71

Define asymptotic.

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 is only sometimes symmetrical.

Question 74

What does a z score of -4 mean?

Question 75

Are distributions always normal?

Question 76

Why do we use standard scores?