Final answer:
The most important type of significance in single-subject research is clinical significance, which assesses the practical impact of a treatment. Validity measures the accuracy of research measurements, and a personality psychologist studies factors influencing job performance. Researchers often use a placebo to control for participant expectations in experiments.
Step-by-step explanation:
The most important type of significance in single-subject research is a. Clinical Significance. Clinical significance refers to the practical importance of a treatment effect - whether it has a real, palpable impact on daily life. In contrast, statistical significance (b) is more about the mathematical likelihood that the treatment effect is not due to chance, external validity (c) pertains to how well the findings can be generalized to other situations, and group comparisons (d) involve comparing one group to another in an experimental setting.
A measurement is considered c. valid if it accurately reflects or measures the concept that researchers are interested in.
A researcher interested in factors making an employee best suited for a job is likely a a. personality psychologist, focusing on individual traits, behaviors, and patterns that might influence job performance.
Sometimes, researchers administer a d. placebo to control for the effects that participant expectation might have on the experiment. This helps to ensure that the resultant data is due to the treatment under investigation rather than the participants' beliefs about the treatment.
The differences in outcomes between a control group receiving a placebo and a treatment group receiving an actual drug may be attributed to treatment variability.
When pharmaceutical companies test the efficacy of a drug, finding a statistically significant difference in outcomes between the experimental and control group allows the conclusion that the drug could be effective for treatment.