Study guide: research conducted for the purpose of verifying previous experimental findings is called: Chapter 1. 5: a research method in which a representative group of people are questioned about their behaviors or attitudes is called: A survey: when researchers want to be sure that known subgroups of the population are represented proportionally in the research, a _____________ sample is used. Bias in the design of the questions: a method of scientific investigation that studies the relationships between variables is called: Correlational: as a person ages, his or her physical strength declines. The relationship between strength and age will show a ___________ coefficient of correlation. Negative: the major advantage of the experimental method is that it: To provide a source of comparison: if you add up all the scores and divide by the number of scores, the result is the: Mean: we, as researchers, must specify precisely what we mean by terms we use.