答案和详解如下： Q1. Which of the following statements regarding various statistical measures is least accurate?
A) The coefficient of variation is calculated by dividing the mean by the standard deviation. B) The correlation coefficient is calculated by dividing the covariance of two random variables by the product of their standard deviations. C) Variance equals the sum of the squared deviations from the mean times the probability that that each outcome will occur. Correct answer is A) The coefficient of variation equals the standard deviation divided by the mean. Q2. Use the results from the following survey of 500 firms to answer the question. Number of Employees
Frequency
300 up to 400 40 400 up to 500 62 500 up to 600 78 600 up to 700 101 700 up to 800 131 800 up to 900 88 The lower boundary of the fifth interval (class) is: A) 700. B) 800. C) 701. Correct answer is A) 700 - 800, lower boundary = 700 Q3. Use the results from the following survey of 500 firms to answer the question. Number of Employees
Frequency
300 up to 400 40 400 up to 500 62 500 up to 600 78 600 up to 700 101 700 up to 800 131 800 up to 900 88 The width of each interval (class) for this frequency table is: A) 101. B) 100. C) 50. Correct answer is B) Max of interval − Min of interval = 100 | 
发表于 2008-12-31 16:24
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