Certain trees grow such that their maximum heights are normally distributed

with a mean height of $10m$ and a standard deviation of $1\mathrm{.}5m.$

a$)$ Draw a normal distribution curve for this data.

b$)$ Use the $68-95-99\mathrm{.}7$ rule to calculate the percentage of trees that are between $8\mathrm{.}5m$ and $13m$

high.