Which option below best describes the difference between an experiment and an observational study?

a. The values in an experiment are chosen at random, but not in an observational study.
b. The values in an observational study are chosen at random, but not in an experiment.
c. The groups in an experiment are chosen at random, but not in an observational study.
d. The groups in an observational are chosen at random, but not in an experiment.

Suppose there are 10 five and six-year-old attending a birthday party. when a 30 year old mother walks into the room with an infant in her arms, what happens to the mean age in the room? what happens to the standard deviation of ages in the room? a. the mean and standard deviation of both change. b. the meaning will change, but the standard deviation will stay approximately the same. c. i mean will stay approximately the same, but the standard deviation will change. d. the mean and standard deviation will both stay approximately the same.

Which value would be a solution for x in the inequality 47-4x< 7

The suare root of 9x plus 7 plus the square rot of 2x equall to 7