At a football stadium, 20% of the fans in attendance were teenagers. If there were 390 teenagers at the football stadium, what was the total number of people at the stadium? Insert the values given in the problem then scale up or down to find the missing value.

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