Question

Which of the following statements about experimental research is most correct?

1) Finding an r coefficient of 0.9 indicates that your independent variable had a strong effect on your dependent variable.
2) Data collection should be done by someone aware of the hypothesis and conditions to ensure it is done correctly, however they should not be involved in group assignment.
3) Participants should be assigned to conditions according to criteria unrelated to the hypothesis, such as age.
4) Using a within-participants design may lead participants to get better at the task the second time they performed it.

Answer 1

The most correct statement about experimental research is that using a within-participants design can result in improved performance due to practice effects. Correlation coefficients indicate relationships but not causation, and experimental procedures should minimize bias.

Step-by-step explanation:

The statement about experimental research that is most correct is: Using a within-participants design may lead participants to get better at the task the second time they perform it. This effect is known as practice effect or carryover effect, and it is a common issue in within-participants or repeated measures designs where the same participants are exposed to all conditions of the experiment. Hence, to control for these practice effects, counterbalancing and other techniques are used. While a high correlation coefficient such as 0.9 does imply a strong relationship between two variables, it does not prove causation. Additionally, the procedural aspects of data collection and participant assignment should be structured to minimize bias and uphold the experimental integrity. Random assignment is usually utilized to help ensure that groups are equivalent at the start of the experiment.