The formula used to measure area of circle is
a.4πr²
b.πr²
c.2πr²
d.πr² + 2r

Which of the following statements would be sufficient to prove that parallelograms pqrs is a rectangle ?

Afair die is cast four times. calculate the probability of obtaining exactly two 6's round to the nearest tenth of a percent

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