问一道题：NO.PZ2017092702000153

问题如下：

Using the data from the table, the difference between the median and the mode is closest to:

选项：

–1.41.

0.00.

1.41.

解释：

B is correct. The median is the value of the middle item of a set of items sorted into ascending or descending order. In an even-numbered sample, we define the median as the mean of the values of items occupying the n/2 and (n + 2)/2 positions (the two middle items). Given Table 2 has six observations, the median is the mean of the third and fourth observations. Because both are–1.20, the median is –1.20. The mode is the most frequently occurring value in a distribution. The only value occurring more than once is –1.20. Because the median and the mode both equal –1.20, their difference is zero.

A is incorrect because –1.41 is the difference between both the identical mode and median with the arithmetic mean. Both differences are: [–1.20 – (0.21)] = –1.41.
C is incorrect because 1.41 is the difference between the arithmetic mean with both the identical mode and median. Both differences are: [0.21 – (–1.20)] = 1.41.