Lison and her family went out to dinner to celebrate the end of the summer. alison agreed to pay the tip from the money she earned from her summer job. the total cost of the meal was $50.00. alison left $9.00 for the tip. what percent tip did alison leave?

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