Chapter 5 Z-Scores

A test of life satisfaction has a mean of u=60. Jenna's test score of X=72 has a z-score of +3.0. what is the standard deviation for this distribution of test scores? a 6 b 2 c 3 d 4

4

Professor Chao's engineering final exam has a mean of u=79 and and standard deviation of 7. After standardizing the exam scores, the mean is u=8 and standard deviation =5. how did professor Chao arrive at these new standardized scores for the exam? a. deciding what values will be simple to calculate b. Selecting the nearest vales that are multiples

deciding what values will be simple to calculate

A distribution has u=50 and standard deviation =6. In a graphical representation of the distribution, where would the score X=20 appear? a Just right of the peak of the curve b Just left of the peak of the score c in the left tail of the curve d in the right tail of the curve

in the left tail of the curve

A sample has a mean of M=64 and a standard deviation of s=3. What is the z-score for a sample score of X=70? a. z=+1.00 b. z=+1.25 c. z=-.75 d. z=+2.00

z=+2.00

WHich of the following z-scores indicates an X value that falls farthest below the mean for the distribution. a.z=-.50 b.z=-1.50 c. z=+2.00 d. z=+1.25

z=-1.50

A researcher has compiled a set of scores witha mean of u=39 and a standard deviation of 4 WHat is the z-score for the raw score X=28? a. z=-.50 b. z=+2.75 z= z=-2.75 d. z=+.60

z=-2.75

A distribution of exam scores has a mean of u=52 and standard deviation of 6. WHat is the z-score for the exam score X=61? a.z=+0.5 b.z=+1.5 c.z=+2. d. z=-1.5

z=+1.5

Solve z-score and a mean of 12.3 with a standard deviation of 1.6 for the following: 1) two standard deviations below the mean 2) one-half of a standard deviation above the mean 3)one-quarter of a standard deviation about the mean 4) three standard deviations below the mean 5) one standard deviation below the mean

1) 9.1 2) 13.1 3) 12.7 4) 7.5 5) 10.7

Fing the z-score for the following: Mean 17 Standard Deviation 2 Orginal scores: 1)18.5 2)16 3)15

1)+0.75 2)-0.50 3)-1.00

Solve for original X score with the following: u=61, standard deviation=8, and the z-score=+1.75. a 53 b 47 c 75 d 69

75

What is necessary to determine the z-score for a raw score in a particular set of scores? a. the median X score and the mean for the set b. the number of scores and standard deviation for the set c. the highest, lowest, and mean scores for the set d. The mean and standard deviation of the set

The mean and standard deviation of the set

What is the benefit of converting raw scores from a sample into z-scores?

The new scores are easier to compare.

True or False After the scores in a distribution are standardized, the revised z-scores are always the same as the original z-scores?

True

True or False Regardless of the values for the original distribution, after standardization the mean for the z-score is always zero, and the standard deviation is always 1.

True

Marisol received a score of X=70 on her chemistry exam and a score of X=59 on her geography exam. The mean for the chemistry exam is u=66, and the mean for the geography exam is u=50. On which exam will Marisol receive a higher grade?

Unknown, you need the standard deviation for each set of exams to determine.

Why would you want to transform a set of raw scores into a set of z-scores? Pick all that apply. a. to make sure all the transformed scores greater than 0 b. to make sure the z-scores are normally distriuted c. to be able to describe the location of a raw score in the distribution of raw scores. d. to make a distribution with a mean of and a standard deviation of 1

c. to be able to describe the location of a raw score in the distribution of raw scores. d. to make a distribution with a mean of and a standard deviation of 1

The distribution for scores on a history exam has u=70 and standard deviation of 4. The distribution for a set of scores on a sociology exam has u=68 and standard deviation of 4. Tenisha scored 76 on both exams. which f the following statements best describes the grades Tenisha will receive on her exams? a. She will receive the same grades because her raw scores are the same b. she will receive a higher grade on the history exam based on standardization c. she will receive a higher grade on the sociology exam based on standardization d. unknown

she will receive a higher grade on the sociology exam based on standardization

A distribution of 1000 test scores has a mean of u=278. Following standardization, what is the standard deviation for this distribution?

standard deviation =1

Solve the z-score with a mean of 49 and the standard deviation of 20.7 for the following: 1) 32 2) 45 3) 66 4) 55

1) -0.82 2) -0.19 3) 0.82 4) 0.29

Solve the z-score with a mean of $1500 for the following: X: 1) $2785 2) $1136 3) $928 4) $3370 5) $709 Standard Deviation: 1) $835.60 2) $170.40 3) $139.20 4) $1011.00 5) $106.40

1) -1.54 2) 2.14 3) 4.11 4) -1.85 5) 7.43

Are standardized scores and z-scores the same thing?

NO

For a population with u=69 and standard deviation = 4, which of the following X scores will convert to a positive z-score of magnitude greater than 1.0 a.X=62 b.X=65 c.X=74 d. X=72

X=74

Is a z-score a standardized score?

YES

What does this equation solve for: X - mean (u) / standard deviation

z-score

Within a population having a standard deviation of 20, the raw score X=75 has a z-score of -1.25. What is the mean for the population? a u=100 b u=125 c u=90 d u=50

u=100

In a distribution, a score of X=60 has a z-score of -3.0. A score of X=85 has a z-score of +2.0. What are the mean and the standard distribution for this population? a. u=50, standard deviation = 10 b u=75, standard deviation = 5 c u=70, standard deviation = 2 d u=68, standard deviation = 4

u=75, standard deviation = 5