Of the last 60 people who went to the cash register at a department store , 14 had blonde hair , 17 had black hair , 26 had brown hair and 3 had red hair . determine the empirical probability that the next person to come to the cash register has black hair

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