Given:
The time to complete an exam is approximately Normal with a mean of 49 minutes and a standard deviation of 9 minutes.
So,
[tex]\begin{gathered} \operatorname{mean}=\mu=49 \\ standarddeviation=\sigma=9 \end{gathered}[/tex]
Given the following figure of the bell curve represents the distribution for testing times.
We will fill in the indicated boxes as follows by calculating the value of each box:
[tex]\begin{gathered} \mu-3\sigma=49-3\cdot9=22 \\ \mu-2\sigma=49-2\cdot9=31 \\ \mu-\sigma=49-9=40 \\ \mu=49 \\ \mu+\sigma=49+9=58 \\ \mu+2\sigma=49+2\cdot9=67 \\ \mu+3\sigma=49+3\cdot9=76 \end{gathered}[/tex]
