A factory has 2400 items arranged in production order. A quality controller considers two sampling plans for selecting 80 items.
Plan A: inspect the first 80 items made after lunch.
Plan B: choose a random starting item from the first 30 items and then inspect every 30th item.
Name the sampling technique used in each plan.
Give one advantage of Plan B over Plan A.
State one circumstance in which Plan B could still produce an unrepresentative sample.
Explain why a different sample of 80 items could lead to a different conclusion about the production process.