Question

Question

An inspector reported a total of 10 defects out of a total batch size of 200 parts. On closer examination, it was determined that 4 defective parts were mistakenly placed in the batch of acceptable items. What is the inspector’s accuracy in this instance? Specifically, what are the values of p₁ and p₂. (b) What was the true fraction defect rate q?

Answer 1

(a)

Actual number of defective units =10+4 = 14

Actual number of good units = 200 - 14 = 186

Number of good units correctly detected by the Inspector = 200-10-4 = 186

Number of defective units correctly detected by the Inspector = 10

-

p1 = Number of good units correctly detected by the Inspector / Actual number of good units

= 186/186

= 1

-

p2 = Number of defective units correctly detected by the Inspector / Actual number of defective units

= 10/14

= 0.7143

--------------------------------------------------------------------

(b)

True fraction defect rate, q = Actual number of defective units / Total batch size

= 14/200

= 0.07