Answer
B
Work Step by Step
Company A:
μ: 8 σ:.15, n = 400
$P(7.8\leq x \leq 8.2 )$ = $P(\frac{7.8-8}{15} \leq z \leq \frac{8.2-8}{15})$ =$P(-0.013 \leq z \leq 0.013 )$ =0.9088-0.0912 = 0.8176
$(0.8176*10000)/400$= 20.44 dollars per rod
Company B
μ: 8 σ:.12, n = 460
$P(7.8\leq x \leq 8.2 )$ = $P(\frac{7.8-8}{12} \leq z \leq \frac{8.2-8}{12})$ =$P(-0.17 \leq z \leq 0.17 )$ = 0.9522- 0.0478= 0.9044
$(0.9044*10000)/460$= 19.66 dollars per rod
Alpha Corporation should use company B as supplier, because the rods per unit are cheaper than with company A.
