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| 1 | |
A key difference between calculating the sample mean and the population mean is: |
| | A) | we use  <![CDATA[<a onClick="window.open('/olcweb/cgi/pluginpop.cgi?it=jpg::::/sites/dl/free/0073521477/944516/ch03_q1.jpg','popWin', 'width=NaN,height=NaN,resizable,scrollbars');" href="#"><img valign="absmiddle" height="16" width="16" border="0" src="/olcweb/styles/shared/linkicons/image.gif"> (0.0K)</a>]]> and n instead of μ and N. |
| | B) | we divide the sum of the observations by n - 1 instead of n. |
| | C) | the sample observations are ranked and the middle value is selected as the population mean. |
| | D) | there are no differences. |
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| 2 | |
Which of the following measures of central location is affected most by extreme values? |
| | A) | Median |
| | B) | Mean |
| | C) | Mode |
| | D) | Variance |
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| 3 | |
The Empirical Rule states that: |
| | A) | for a bell shaped frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation. |
| | B) | for a positively skewed frequency distribution, approximately 68% of the observations are in the range of plus or minus one standard deviation. |
| | C) | for a bell shaped frequency distribution, approximately 75% of the observations are in the range of plus or minus one standard deviation. |
| | D) | for a positively skewed frequency distribution, approximately 75% of the observations are in the range of plus or minus one standard deviation. |
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| 4 | |
Which measure of central tendency reports the value that occurs with the highest frequency? |
| | A) | Mean |
| | B) | Median |
| | C) | Mode |
| | D) | Standard deviation |
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| 5 | |
An example of Chebyshev's Theorem is: |
| | A) | for a bell shaped frequency distribution, at least 95% of the observations are in the range of plus or minus two standard deviations from the mean. |
| | B) | for a negatively skewed frequency distribution, at least 95% of the observations are in the range of plus or minus two standard deviations from the mean. |
| | C) | for any frequency distribution, at least 75% of the observations are in the range of plus or minus two standard deviations from the mean. |
| | D) | for a positively skewed frequency distribution, at least 68% of the observations are in the range of plus or minus two standard deviations from the mean. |
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| 6 | |
In comparing two different samples of 100 observations, sample "A" has a mean of 10 and a standard deviation of 10. The sample "B" has a mean of 10 and a standard deviation of 50. The two samples are: |
| | A) | exactly the same. |
| | B) | are centered at 10, but sample "A"s data is more concentrated near the mean. |
| | C) | are centered at 10, but sample "B"s data is more concentrated near the mean. |
| | D) | positively skewed. |
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| 7 | |
For a distribution, the mean is 5, the median is 15, and the mode is 20. Based on this information, the distribution is: |
| | A) | positively skewed. |
| | B) | negatively skewed. |
| | C) | symmetric. |
| | D) | bell-shaped. |
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| 8 | |
In a positively skewed distribution, which measure of central tendency is the largest? |
| | A) | Mean |
| | B) | Median |
| | C) | Mode |
| | D) | Variance |
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| 9 | |
Which of the following statistics is a measure of dispersion? |
| | A) | Mean |
| | B) | Median |
| | C) | Mode |
| | D) | Standard deviation |
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| 10 | |
What is true about the range? |
| | A) | Only two values are used in its calculation. |
| | B) | It is in different units than the mean. |
| | C) | It can be used for nominal data. |
| | D) | All values are used in its calculation. |
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| 11 | |
The numerator of the mean deviation is: |
| | A) | the sum of squared deviations from the mean. |
| | B) | the variance. |
| | C) | the sum of the absolute values of deviations from the mean. |
| | D) | always reported in units squared. |
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| 12 | |
The standard deviation is: |
| | A) | based on squared deviations from the mean. |
| | B) | expressed in the same units as the mean. |
| | C) | uses all the observations in its calculation. |
| | D) | all of the above. |
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| 13 | |
In a negatively skewed distribution: |
| | A) | the mean, median, and mode are all equal. |
| | B) | the mean is larger than the median. |
| | C) | the median is larger than the mean. |
| | D) | the standard deviation must be larger than the mean or the median. |
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