When analyzing categorical data, stem and leaf display is an appropriate plot.

X is a discrete random variable that can have values fr...

单项选择题X is a discrete random variable that can have values from 0 to infinity, and occurrences of the events X counts are independent. The standard deviation of X is equal to the square root of the mean. The probability distribution of X is a(n) （）distribution.

The empirical rule tells us that approximately of the v...

单项选择题The empirical rule tells us that approximately of the values cluster within a distance of 1 standard deviation from the mean for a bell-shaped distribution（）

The reason that we prefer the sample standard deviation...

单项选择题The reason that we prefer the sample standard deviation as our measure of typical variation instead of the sample variance is that（）