To find the area to the left of x=73 under a normal distribution curve:
1. Find the corresponding z, use the next formula:
[tex]z=\frac{(x-\operatorname{mean})}{\text{standard deviation}}[/tex][tex]\begin{gathered} z=\frac{73-71}{2} \\ \\ z=\frac{2}{2} \\ \\ \\ z=1 \end{gathered}[/tex]2. Find the z-score corrsponding to z=1, use a z score table:
The area to the left of z is equal to the corresponding z-score.
Then, the area to the left of x=73 is 0.8413
