1) If you are interested in comparing variation in sales for small and large stores selling similar goods, which of the following is the most appropriate measure of dispersion?
A) the range
B) the interquartile range
C) the standard deviation
D) the coefficient of variation
2) Suppose you are told that the mean of a sample is below the median. What does this information suggest about the distribution?
A) The distribution is symmetric.
B) The distribution is skewed to the right or positively skewed.
C) The distribution is skewed to the left or negatively skewed.
D) There is insufficient information to determine the shape of the distribution.
3) For the following scatter plot, what would be your best estimate of the correlation coefficient?
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A) -0.8
B) -1.0
C) 0.0
D) -0.3
4) Given a set of 25 observations, for what value of the correlation coefficient would we be able to say that there is evidence that a relationship exists between the two variables?
A).jpg”> ? 0.40
B).jpg”> ? 0.35
C).jpg”> ? 0.30
D).jpg”> ? 0.25
5) Which of the following statements is true about the correlation coefficient and covariance?
A) The covariance is the preferred measure of the relationship between two variables since it is generally larger than the correlation coefficient.
B) The correlation coefficient is a preferred measure of the relationship between two variables since its calculation is easier than the covariance.
C) The covariance is a standardized measure of the linear relationship between two variables.
D) The covariance and corresponding correlation coefficient are represented by different signs, one is negative while the other is positive and vice versa.
6) For the following scatter plot, what would be your best estimate of the correlation coefficient?
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A) 1.0
B) 0.7
C) 0.3
D) 0.1
7) Which of the following descriptive statistics is least affected by outliers?
A) mean
B) median
C) range
D) standard deviation
8) Which of the following statements is true?
A) The correlation coefficient is always greater than the covariance.
B) The covariance is always greater than the correlation coefficient.
C) The covariance may be equal to the correlation coefficient.
D) Neither the covariance nor the correlation coefficient can be equal to zero.
9) Which measures of central location are not affected by extremely small or extremely large data values?
A) arithmetic mean and median
B) median and mode
C) mode and arithmetic mean
D) geometric mean and arithmetic mean
10) Suppose you are told that sales this year are 30% higher than they were six years ago. What has been the average annual increase in sales over the past six years?
A) 5.0%
B) 4.5%
C) 4%
D) 3.5%
