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 the first 2,000 light bulbs in the production line
B). retesting 100 light bulbs that have already been tested
C). testing every fiftieth light bulb in the production line
D). testing the last 4,000 bulbs in the production line
C). testing every fiftieth light bulb in the production line
This method of sampling ensures that a representative sample of light bulbs from across the production line is tested, rather than just focusing on the first or last bulbs. This will provide a more accurate estimation of the overall percentage of defective light bulbs in the production line.