The graph shows the weight and fuel efficiency, in miles per gallon, for a selection of vehicles. Which is the best estimate of the correlation coefficient of the line of best fit?
A. -0.91
B. -0.23
C. 0.68
D. 0.89

Agroup of student volunteers participates in a study designed to assess several behavioral interventions for improving output in a repetitive task. prior to the beginning of the study, all volunteers unknowingly observed, and their output is measured. at the beginning of the study, prior to any intervention, the volunteers perform the same task under the observation of a study administrator, and their overall output increases. which of the following terms describes this phenomenon? a. simpson's paradox b. hawthorne effect are d. novelty effect d. pygmalion effect e. observer-expectancy effect