Answer:
The probability that a defective ball bearing was manufactured on a Friday is 0.375.
Step-by-step explanation:
The conditional probability of an events X given that another event A has already occurred is:
[tex]P(X|A)=\frac{P(A|X)P(X)}{P(A)}[/tex]
The information provided is as follows:
P (D|M) = 0.08
P (D|Tu) = 0.04
P (D|W) = 0.04
P (D|Th) = 0.04
P (D|F) = 0.12
It is provided that the Company manufactures an equal amount of ball bearings, 20% on each weekday, i.e.
P (M) = P (Tu) = P (W) = P (Th) = P (F) = 0.20
Compute the probability of manufacturing a defective ball bearing on any given day as follows:
[tex]P(D)=P(D|M)P(M)+P(D|Tu)P(Tu)+P(D|W)P(W)\\+P(D|Th)P(Th)+P(D|F)P(F)[/tex]
[tex]=(0.08\times 0.20)+(0.04\times 0.20)+(0.04\times 0.20)+(0.04\times 0.20)+(0.12\times 0.20)\\\\=0.064[/tex]
Compute the probability that a defective ball bearing was manufactured on a Friday as follows:
[tex]P(F|D)=\frac{(D|F)P(F)}{P(D)}[/tex]
[tex]=\frac{0.12\times 0.20}{0.064}\\\\=0.375[/tex]
Thus, the probability that a defective ball bearing was manufactured on a Friday is 0.375.
