What are you finding or solving?
81ft(yd/3ft)*111ft(yd/3ft)*2in(yd/36in)=55.5 yd^3
So 55 1/2 cubic yards of topsoil are needed.
Since 74% of the middle area is bounded, this means that
there is 13% on the left side, and another 13% on the right side.
P (left) = 0.13
P (right ) = 1 - 0.13 = 0.87
At this P values, the z scores are approximately:
z score (left) = -2.22
<span>z score (right) = 1.13</span>
