stats chapter five test 2

For a population with μ = 90 and σ = 12, what is the z-score corresponding to X = 102? Answer +0.50 +1.00 +1.20 +12.00

+1.00

A sample with a mean of M = 70 and a standard deviation of s = 15 is being transformed into z-scores. After the transformation, what is the standard deviation for the sample of z-scores? Answer 0 1 n - 1 n

1

In a population with μ = 70, a score of X = 68 corresponds to a z-score of z = -0.50. What is the population standard deviation? Answer 1 2 4 Cannot be determined without additional information.

4

In a population of scores, X = 50 corresponds to z = +2.00 and X = 35 corresponds to z = -1.00. What is the population mean? Answer 35 40 37.5 45

40

A set of scores has a mean of μ = 63 and a standard deviation of σ = 8. If these scores are standardized so that the new distribution has μ = 50 and σ = 10, what new value would be obtained for a score of X = 59 from the original distribution? Answer The score would still be X = 59. 45 46 55

45

What location in a distribution corresponds to ? Answer Above the mean by 3 points. Above the mean by a distance equal to three standard deviations. Below the mean by 3 points. Below the mean by a distance equal to three standard deviations.

Below the mean by a distance equal to three standard deviations.

Which of the following is an advantage of transforming X values into z-scores? Answer All negative numbers are eliminated. The distribution is transformed to a normal shape. All scores are moved closer to the mean. Dissimilar distributions can be compared.

Dissimilar distributions can be compared.

In a sample, X = 70 corresponds to z= +2.00 and X = 65corresponds to z = +1.00. What are the sample mean and standard deviation? Answer M = 60 and s = 5 M = 60 and s = 10 M = 50 and s = 10 M = 50 and s = 5

M = 60 and s = 5

In a sample with a standard deviation of s = 4, a score of X = 64 corresponds to z = -0.50. What is the sample mean? Answer M = 62 M = 60 M = 66 M = 68

M = 66

Last week Sarah had exams in math and Spanish. On the math exam, the mean was μ = 30 with σ = 5, and Sarah had a score of X = 45. On the Spanish exam, the mean was μ = 60 with σ = 6, and Sarah had a score of X = 65. For which class should Sarah expect the better grade? Answer Math Spanish The grades should be the same because the two exam scores are in the same location. There is not enough information to determine which is the better grade.

Math

Under what circumstances would a score that is 20 points above the mean be considered an extreme score? Answer When the mean is much larger than 20. When the standard deviation is much larger than 20. When the mean is much smaller than 20. When the standard deviation is much smaller than 20.

When the standard deviation is much smaller than 20.

A distribution with μ = 35 and σ = 8 is being standardized so that the new mean and standard deviation will be μ = 50 and σ = 10. When the distribution is standardized, what value will be obtained for a score of X = 39 from the original distribution? Answer X = 54 X = 55 X = 1.10 Impossible to determine without more information.

X = 55

For a sample with M = 72 and s = 4, what is the X value corresponding to z = -2.00? Answer X = 70 X = 68 X = 64 X = 60

X = 64

For the past 20 years, the high temperature on April 15 has averaged μ = 60 degrees with a standard deviation of σ = 4. Last year, the high temperature was 75 degrees. Based on this information, last year's temperature on April 15 was _______. Answer a little above average far above average above average, but it is impossible to describe how much above average There is not enough information to compare last year with the average.

far above average

standardized distribution

s composed of scores that have been transformed to create predetermined values for μ and σ

z-score

specifies the precise location of each X value within a distribution

A population with μ = 90 and σ = 20 is transformed into z-scores. After the transformation, what is the mean for the population of z-scores? Answer μ = 80 μ = 1.00 μ = 0 Cannot be determined from the information given.

μ = 0

A score of X = 75 is obtained from a population. Which set of population parameters would make X = 75 an extreme, unrepresentative score? Answer μ = 65 and σ = 8 μ = 65 and σ = 3 μ = 70 and σ = 8 μ = 70 and σ = 3

μ = 65 and σ = 3