Since we have that 316 CDs are defective from 1938, then:
![1938─316=1622](https://img.qammunity.org/2023/formulas/mathematics/high-school/gfbb8wbq5jq9ncfoh09opbv0x6b0lmclpv.png)
A) we have that 1622 good CDs were produced.
B) If A is the probability that all 4 cds are good if you are selecting without replacement is:
![\begin{gathered} P(A)=((1622)/(1938))((1621)/(1937))((1622)/(1936))((1619)/(1935))=0.490372393 \\ P(A)=0.4904 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/qqqobfoydck4g2222rdgiohrznvboppzcq.png)
C)In this case, we can use the 5% guideline, since the sample size is 4 and it's less than the 5% of 1938 (option C).
D) We can check this by calculating the probability assuming each selection is with replacement:
![\begin{gathered} P(A)=((1622)/(1938))^4=0.490668648 \\ P(A)=0.4907 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/kvy60u4ey54ug8eyhto91q3afikllhfbit.png)
Then, the probability that all 4 CDs are good assuming this situation is independent is 0.4907
E)We have seen that both probabilities are almost the same, but in most cases, it's best to use the 5% guideline. Therefore, the answer D is the best choise because the 5% guideline is very accurate in this case (otpion B)