If the population distribution is unknown, in most cases the sampling distribution of the mean can be approximated by the normal distribution if the sample size is at least 15 observations.

When analyzing categorical data, stem and leaf display ...

判断题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（）