A quality control manager wants to determine the percentage of defective light bulbs in the production line. Which of the following sampling methods would most likely lead to a valid inference?
A. testing every fiftieth light bulb in the production line
B. testing the first 2,000 light bulbs in the production line
C. testing the last 4,000 bulbs in the production line
D. retesting 100 light bulbs that have already been tested
A. testing every fiftieth light bulb in the production line
This sampling method allows for a representative sample of the entire production line to be tested, without bias towards certain portions of the production. This would most likely lead to a valid inference regarding the percentage of defective light bulbs in the production line.