商务统计学章节测试课后答案2024春

第三章测试

1.Simon Arnett, Director of Human Resources, is exploring employee absenteeism at the Buderim Bottling during the last operating year. A sample of six personnel records produced the following data: 0, 2, 4, 7, 2, 9. The variance of the number absences per employee is ____________.
A:3.11 B:9.67 C:11.6 D:3.41
答案:C
2.Jessica Salas, Managing Director of Salas Products, is reviewing the warranty policy for her company’s new model of car batteries. Life tests performed on a sample of 100 batteries indicated: (1) an average life of 75 months, (2) a standard deviation of 5 months, and (3) battery life is approximately normally distributed. Approximately 68% of the batteries will last between ________________.
A:55 and 95 months B:60 and 90 months C:65 and 85 months D:70 and 80 months 3.The average starting salary for graduates at a university is $25,000 with a standard deviation of $2000. A histogram of the data shows the shape to be very erratic so Chebyshev’s Theorem should be used. How many of the graduates would have a starting salary between 21,000 and 29,000?
A:at least 75% B:at least 95% C:at least 89% D:at least 68% 4.The sample standard deviation is found by taking the square root of _______.
A:the coefficient of variation B:the sample variance C:the mean absolute deviation D:the sample mean 5.The number of standard deviations that a value (X) is above or below the mean is the _______.
A:absolute deviation B:Z score C:interquartile range D:coefficient of variation 6.In a histogram, the proportion of the total area that must be to the left of the median is（ ）
A:exactly 0.50. B:less than 0.50 if the distribution is skewed to the left C:between 0.25 and 0.60 if the distribution is symmetric and unimodal D:more than 0.50 if the distribution is skewed to the right 7.Which of the following is NOT a measure of central tendency?
A:mean B:mode C:variance D:median 8.Another term for average is ____________.
A:mode B:mean C:variance D:median 9.If the mean of a distribution is greater than the median, then the distribution is ____________.
A:not skewed B:symmetrical about its mean C:skewed to the left D:skewed to the right  10.The mean is not affected by the extreme values.
A:对 B:错