Which scenario demonstrates a random sampling method for testing in accordance with Army guidelines?

Which scenario demonstrates a random sampling method for testing in accordance with Army guidelines?

• A. Draw a number from a hat; every soldier whose DOD ID ends with that number is tested.
• B. Test only volunteers.
• C. Test only on weekends.
• D. Test every soldier in the unit.

Answer: (A)

Random sampling means giving each person an equal chance to be chosen, so the selection reflects the whole group rather than individual preferences or convenient timing. Drawing a number from a hat and testing every soldier whose DOD ID ends with that number is random because the selection is determined by chance, not by who volunteers or when you can test. If the distribution of ID endings is roughly even, this method yields a representative subset. In contrast, testing only volunteers relies on self-selection and can bias results; testing only on weekends isn’t randomness, it’s a scheduling constraint; testing everyone is a census, not a sample.

Random sampling means giving each person an equal chance to be chosen, so the selection reflects the whole group rather than individual preferences or convenient timing. Drawing a number from a hat and testing every soldier whose DOD ID ends with that number is random because the selection is determined by chance, not by who volunteers or when you can test. If the distribution of ID endings is roughly even, this method yields a representative subset. In contrast, testing only volunteers relies on self-selection and can bias results; testing only on weekends isn’t randomness, it’s a scheduling constraint; testing everyone is a census, not a sample.