In experimental research, randomization is typically applied to what?

In experimental research, randomization is typically applied to what?

• A. random assignment of participants to different treatment conditions.
• B. random sampling from the population.
• C. random order of data collection.
• D. randomizing the measurement scale.

Answer: (A)

Random assignment to treatment conditions is used to ensure that the groups being compared are equivalent at the start of the experiment. By randomly placing participants into different conditions, individual differences—whether known or unknown—tend to be distributed evenly across groups. This minimizes confounding influences, so differences in outcomes can be attributed to the manipulated variable rather than preexisting characteristics. This is what allows for causal inferences and supports the use of standard statistical tests that assume groups are comparable. Random sampling from the population, while important for generalizing findings, addresses external validity rather than internal control within the experiment. An experiment can use random assignment to maintain internal validity even with a non-representative sample. Random order of data collection can help reduce biases related to when measurements are taken, especially in repeated measures designs, but it is not the primary purpose of randomization in experimental design. Randomizing the measurement scale isn’t a concept used in this context—the scales themselves are fixed properties of the measurement instrument, not something randomized.

Random assignment to treatment conditions is used to ensure that the groups being compared are equivalent at the start of the experiment. By randomly placing participants into different conditions, individual differences—whether known or unknown—tend to be distributed evenly across groups. This minimizes confounding influences, so differences in outcomes can be attributed to the manipulated variable rather than preexisting characteristics. This is what allows for causal inferences and supports the use of standard statistical tests that assume groups are comparable.

Random sampling from the population, while important for generalizing findings, addresses external validity rather than internal control within the experiment. An experiment can use random assignment to maintain internal validity even with a non-representative sample.

Random order of data collection can help reduce biases related to when measurements are taken, especially in repeated measures designs, but it is not the primary purpose of randomization in experimental design.

Randomizing the measurement scale isn’t a concept used in this context—the scales themselves are fixed properties of the measurement instrument, not something randomized.