3.
z = X1 - u = 2400 - 2370 = .08
σ
375
area = .0319 or 03.19%
Z = x2-u = 2600 - 2370 = .61
σ
375
area = .2291 or 22.91%
In order to find the shaded area, we must subtract the smallest area from the largest: 22.91%
- 3.19% = 19.72%.
There is a 19.72% chance that the supply expenditures for a given month are between 00 and
00. (Reference: Frames 67-68.)
4.
Area is 80%/2 = 40% or .4000, Therefore, z = 1.29.
b = u + zσ = 2370 + 1.29 (375) = 53.75
a = u - zσ = 2370 - 1.29 (375) = 86.25
80% of the time, supply expenses will be between 86.25 and 53.75. (Reference:
Frames 69-70.)
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FI0921
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