Write a code to add 4 known numbers​

Pj conducts an experimental study on the effects of soft music during high stakes science testing. he randomly assigns students at the school. in one condition he does not provide music for testing while in the other group he does provide the music. he administers a pretest at the beginning of the year and a posttest at the end of the year. pj’s design is best described as a: a. static group comparisonb. pretest-posttest control group designc. control-group-time-series designd. nonrandomized control-group pretest-posttest design

Atraffic cop has pulled over a speeder, only to discover that he has stopped a close friend. the police officer is torn, because his professional obligations demand that he punish the speeder, but his personal obligations suggest that he should give a friend a break. what is this called?

Identify and describe the purposes of taxation.