28. frequency distribution
29. relative frequency distributions
30. the mean of the random variable X isthe sum of the products XP for all values of X.
31. the mean of a random variable X isalso called the expected value of X or the mean of the probability distributionof X
32. In any group of data, most of thedata are within about 3 standard deviations above or below the mean.
33. The process of subtracting the meanfrom each value and then dividing the result by the standard deviation iscalled standardization. Its a useful tool because for each data value, itprovides a measure of position relative to the rest of the data independentlyof the variable for which the data was collected and the units of the variable.
34. universal set
35. median 把曲线下面的面积平均分成两块面积相等的部分,mean要算上这块面积的重量,所以og上那个图的mean要在median的右边,因为越往右,越重
36. 所以median是halving point, 而mean is the balance point
37. box-and-whisker plot 5个点L Q1 Q2 Q3 G 可以立刻看到median, interquartile range and range.
38. 正态分布:2%,14%,34%,34%,14%,2%
了解了这些信息,你还可以参考小编为你整理的:
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