Answer: systematic
Step-by-step explanation:
- In random sampling researcher choose elements randomly for sample .
- In convenience sampling individuals are selected as per his convenience and comfort.
- In systematic sampling individuals are selected in a systematic way by using a fix periodic interval k from the entire population .
- In cluster sampling clusters (of homogeneous elements) are selected to make a sample.
Given, When grading English papers, the instructor checks every 4th paper for plagiarism which expresses a fixed periodic interval.
Hence, this is systematic sampling.
