Suppose that amount spent by students on textbooks this semester has approximately a bell-shaped distribution. The mean amount spent was 300 and the standard deviation is 100 . Which choice best completes the following sentence? About 68 of students spent between ____.
a. 300 and 400
b. 200 and 400
c. 100 and 500
d. 266 and 334
Q. 2Scores on an achievement test averaged 70 with a standard deviation of 10 . Serena's score was 85 . What was her standardized score (also called a z-score)?
a. 1.5
b. 1.5
c. 15
d. 85
Q. 3Which of the following best describes the standardized (z) score for an observation?
a. It is the number of standard deviations the observation falls from the mean.
b. It is the most common score for that type of observation.
c. It is one standard deviation more than the observation.
d. It is the center of the list of scores from which the observation was taken.
Q. 4The possible values for a standardized score (z-score)
a. can be any number: positive, negative, or 0.
b. must be within the range from -3 to 3
c. must be non-negative.
d. must be strictly positive.
Q. 5Which of the following would indicate that a dataset is not bell-shaped?
a. The range is equal to 5 standard deviations.
b. The range is larger than the interquartile range.
c. The mean is much smaller than the median.
d. There are no outliers.
Q. 6For a large sample of blood pressure values, the mean is 120 and the standard deviation is 10 . Assuming a bell-shaped curve, which interval is likely to be about the interval from the minimum to maximum blood pressures in the sample?
a. 120 to 150
b. 110 to 130
c. 90 to 150
d. 50 to 190
Q. 7For a large sample of blood pressure values, the mean is 120 and the standard deviation is 10 . Assuming a bell-shaped curve, which interval is likely to be about the interval that contains 95 of the blood pressures in the sample?
a. 110 to 130
b. 100 to 140
c. 90 to 150
d. 50 to 190
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