A factory wants to estimate the proportion of defective bolts produced in a day. Bolts come off the assembly line one at a time. The quality engineer randomly selects a starting position between 1 and 50 and then inspects every 50th bolt thereafter throughout the shift.
Which sampling method is being used?
- A
Cluster sample
- Bcheck_circle
Systematic sample
- C
Convenience sample
- D
Simple random sample
Explanation
Selecting every kth element after a random start is a systematic sample. It is not an SRS because not all possible groups of bolts have equal probability of being chosen.