The amount of time a student spent studying for an exam is an example ofa continuous variable. ( )
一个简单随机样本的数据为5,6,5,8,5,9,则该组数据的众数为______ 。
If a variable follow a Poisson distribution(泊松分布), then their( ).
A. mean equals the standard deviation.
B. median equals the standard deviation.
C. mean equals the variance.
D. median equals the variance.
The standardized normal distribution(标准正态分布)( ).
A. has a mean of 0 and a standard deviation of 1.
B. has a mean of 1 and a variance of 0.
C. has an area equal to 0.5.
D. cannot be used to approximate discrete probability distributions.
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