Random sampling of multiple units ensures what?

Random sampling of multiple units ensures what?

• A. It is influenced by preconceived notions or convenience.
• B. The selection of units is not influenced by preconceived notions or convenience.
• C. Sampling must include all units.
• D. It cannot be used in multi-unit dwellings.

Answer: (B)

Random sampling aims to prevent bias when choosing which units to test. By giving each unit a known chance of being selected, the process isn’t swayed by what the investigator expects, by convenience, or by prior knowledge about which units might show higher or lower lead levels. This helps produce a sample that more accurately represents the whole population of units, so conclusions drawn from the sample are more generalizable. That’s why the best choice says the selection isn’t influenced by preconceived notions or convenience. It’s not required to include every unit—the essence of random sampling is choosing a subset in an unbiased way. And yes, random sampling can be used in buildings with multiple units; it’s not restricted to single-unit settings.

Random sampling aims to prevent bias when choosing which units to test. By giving each unit a known chance of being selected, the process isn’t swayed by what the investigator expects, by convenience, or by prior knowledge about which units might show higher or lower lead levels. This helps produce a sample that more accurately represents the whole population of units, so conclusions drawn from the sample are more generalizable. That’s why the best choice says the selection isn’t influenced by preconceived notions or convenience. It’s not required to include every unit—the essence of random sampling is choosing a subset in an unbiased way. And yes, random sampling can be used in buildings with multiple units; it’s not restricted to single-unit settings.