题目

The residence of town X participated in a survey to study the number of hours per week each resident spent watching TV.The distribution of the results of the survey had a mean of 21 hours and a standard deviation of hours.The number of hours that pat,a resident of town X watched TV last week was between 1 and 2 standard deviations below the mean.Which of the following could be the number of hours that pat watched TV last week?30/B,20/C,18/D,12/E,6
请算出答案和过程说明思维路线.
在下十分感谢.

提问时间：2020-08-07

答案

你题目漏打数字了.The distribution of the results of the survey had a mean of 21 hours and a standard deviation of____ hours.我百度了一下,这里的数字应该是6.建议你复习一下均值mean和标准差standard deviat...