Statistics Workshop Quiz
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Suppose a student received a raw score of 41 which corresponded to the 67th percentile. What does this information mean to the teacher?
The correct answer is A. A percentile is the value or score on the ordered array of data that indicates the percentage of the scores that fall at or below that value. The third quartile establishes the point where 75% of the score are below it. Therefore, at the 67th percentile, this student did not score above the third quartile.
2 / 11
Which of the following measures of central tendency is MOST strongly influenced by extreme scores?
The correct answer is A. The mean is most greatly influenced by extreme scores.
3 / 11
Given a normal distribution of student scores, what percentage of the scores will fall within two standard deviations of the mean?
The correct answer is C. 95% of the data points will fall between two standard deviations of the mean. Choice B, 68%, shows the percentage of data points that will fall within one standard deviation of the mean. Choice A is incorrect because the standard deviation includes the area on both sides of the mean.
4 / 11
Which of the following BEST describes what a Pearson coefficient of zero between scores on two tests would indicate to a teacher?
The scores on the two tests are ...
The correct answer is B. A Pearson coefficient of zero indicates that the scores on the two tests are not related in a reliable or predictable way.
5 / 11
Which of the following assessments would be MOST likely to produce a normal curve when graphing the results?
The correct answer is D. The normal curve is most likely to apply to a large, statistically “normal” population.
6 / 11
If the graph of a data distribution shows that the mean is graphed to the right of the mode, which of the following is most likely true?
The correct answer is A. In a positively skewed frequency distribution, the mean moves to the right of the mode and the majority of the scores fall below the mean. For a frequency distribution that is negatively skewed, the mean moves to the left of the mode and is shaped so that the majority of its scores fall above its mean. In a positively skewed distribution, the median is generally less than the mean.
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What would a large standard deviation most likely indicate to a teacher?
The correct answer is C. A large standard deviation means an excessive spread of data well dispersed away from the mean. A small standard deviation indicates a tight cluster of data points near the mean.
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Given a data set with a small range, which of the following would be the BEST measure of central tendency?
The correct answer is A. The mean is considered the best measure of central tendency, unless exaggerated by extreme scores.
9 / 11
Which of the following BEST describes a graph of a bimodal distribution?
The correct answer is B. "Bimodal" means that there are two modes or peaks within the same distribution of data. The two modes will not necessary reflect two extremes and may be clustered near one another.
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What is the numeric difference between the mode and the median of the following set of scores?
The correct answer is B. The mode (most frequently occurring score) is 75 and the median (which divides a distribution exactly in half) is 60. 75 − 60 = 15.
11 / 11
What is the unbiased standard deviation of the following sample?
Step 2: Subtracting the mean from each score.
Step 3: Squaring the result for each score.
Step 4: Adding the results (16 + 4 +0 + 4 + 16) = 40
Step 5: Dividing 40 by the number of scores minus 1 = 10
Step 6: The square root of 10 is approximately 3.16.
The average score is 41%
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