Arock is thrown in the air from the edge of a seaside cliff. its height in feet is represented by f(x) = –16(x2 – 3x – 18), where x is the number of seconds since the rock was thrown. the height of the rock is 0 feet when it hits the water. how long does it take the rock to hit the water? how many seconds?

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