Inspector's Dilemma

You're a quality inspector. Your job is to check incoming lots of parts. You can't check every part, so you use a sampling plan.

Your task is to follow the plan and see what happens. Good luck!

Lot 1 of 5

Your Sampling Plan:

  • Lot Size ($N$): 1,000
  • Sample Size ($n$): 99
  • Acceptance Number ($c$): 4

RULE: If you find more than 4 defects, you MUST REJECT the lot.

A truck from "Reliable Parts Inc." arrives...

You take your sample of 99 and find...

Since 5 > 4, you MUST REJECT THE LOT.

Inspection Shift Over

You inspected 5 lots.

You encountered 2 "Risk" events!

Acceptance sampling doesn't guarantee 100% quality. It's a game of risk!

  • You risked upsetting a good supplier (Producer's Risk).
  • You risked accepting a bad lot (Consumer's Risk).

Producer's Risk!

The lot was actually 1.5% defective (a GOOD lot), but your sample had 5 defects.

Because you (correctly) followed the plan and rejected it, you've just upset a good supplier!