91影视

Tall girls:

The population distribution is given to be $\mathrm{N}(64,2.5)$, which means a normal distribution with mean $64$and standard deviation $2.5$.

$渭=64$

$蟽=2.5$

A general normal distribution with mean $渭$ and standard deviation $蟽$is of the form:

The graph of the population distribution is

Tall girls:

$20$individuals are in the sample

We also know that approximately

$渭=64$

$蟽=2.5$

The width of all bars should be equal and the height should be equal to the number of students.

The bars should be roughly centered about $64$and the range of values should be within $2$standard deviations of the mean.

Dot plot:

Draw a number line and place dots above the corresponding numbers which should be centered at about $64$and the range of values should be within $2$standard deviations of the mean.