Normal Distributions-Chap 2-MC

A distribution of test scores is not symmetric. Which of the following is the best estimate of the z-score of the third quartile?

• 0.67

• 0.75

• 1.00

• 1.41

• This z-score cannot be estimated from the information given.

A data set of test scores is being transformed by applying the following rule to each of the raw scores: Transformed score = 3.5(raw score) + 6.2. Which of the following is NOT true?

• The mean transformed score equals 3.5(the mean raw score) + 6.2.

• The median transformed score equals 3.5(the median raw score) + 6.2.

• The range of the transformed scores equals 3.5(the range of the raw scores) + 6.2.

• The standard deviation of the transformed scores equals 3.5(the standard deviation of the raw scores).

• The IQR of the transformed scores equals 3.5(the IQR of the raw scores).

The distribution of the diameters of a particular variety of oranges is approximately normal with a standard deviation of 0.3 inch. How does the diameter of an orange at the 67th percentile compare with the mean diameter?

• 0.201 inch below the mean

• 0.132 inch below the mean

• 0.132 inch above the mean

• 0.201 inch above the mean

• 0.740 inch above the mean

The weight of adult male grizzly bears living in the wild in the continental United States is approximately normally distributed with a mean of 500 pounds and a standard deviation of 50 pounds. The weight of adult female grizzly bears is approximately normally distributed with a mean of 300 pounds and a standard deviation of 40 pounds. Approximately, what would be the weight of a female grizzly bear with the same standardized score (z-score) as a male grizzly bear with a weight of 530 pounds?

• 276 pounds

• 324 pounds

• 330 pounds

• 340 pounds

• 530 pounds

For a sample of 42 rabbits, the mean weight is 5 pounds and the standard deviation of weights is 3 pounds. Which of the following is most likely true about the weights for the rabbits in this sample?

• The distribution of weights is approximately normal because the sample size is 42, and therefore the central limit theorem applies.

• The distribution of weights is approximately normal because the standard deviation is less than the mean.

• The distribution of weights is skewed to the right because the least possible weight is within 2 standard deviations of the mean.

• The distribution of weights is skewed to the left because the least possible weight is within 2 standard deviations of the mean.

• The distribution of weights has a median that is greater than the mean.

The commuting time for a student to travel from home to a college campus is normally distributed with a mean of 30 minutes and a standard deviation of 5 minutes. If the student leaves home at 8:25 A.M., what is the probability that the student will arrive at the college campus later than 9 A.M.?

• 0.16

• 0.32

• 0.50

• 0.84

• 1.00

Students in a large psychology class measured the time, in seconds, it took each of them to perform a certain task. The times were later converted to minutes. If a student had a standardized score of z = 1.72 before the conversion, what is the standardized score for the student after the conversion?

• z = 0.26

• z = 1.03

• z = 1.72

• z = 1.98

• The standardized score for the student after the conversion cannot be determined.

A company wanted to determine the health care costs of its employees. A sample of 25 employees were interviewed and their medical expenses for the previous year were determined. Later the company discovered that the highest medical expense in the sample was mistakenly recorded as 10 times the actual amount. However, after correcting the error, the corrected amount was still greater than or equal to any other medical expense in the sample. Which of the following sample statistics must have remained the same after the correction was made?

• Mean

• Median

• Mode

• Range

• Variance

At a college the scores on the chemistry final exam are approximately normally distributed, with a mean of 75 and a standard deviation of 12. The scores on the calculus final are also approximately normally distributed, with a mean of 80 and a standard deviation of 8. A student scored 81 on the chemistry final and 84 on the calculus final. Relative to the students in each respective class, in which subject did this student do better?

• The student did better in chemistry.

• The student did better in calculus.

• The student did equally well in each course.

• There is no basis for comparison, since the subjects are different from each other and are in different departments.

• There is not enough information for comparison, because the number of students in each class is not known.

Suppose that the distribution of a set of scores has a mean of 47 and a standard deviation of 14. If 4 is added to each score, what will be the mean and the standard deviation of the distribution of new scores?

• Mean: 51, Standard Deviation: 14

• Mean: 51, Standard Deviation: 18

• Mean: 47, Standard Deviation: 14

• Mean: 47, Standard Deviation: 16

• Mean: 47, Standard Deviation: 18