Which made Chinese exploration of the Indian Ocean possible?

Music the height of a wave or the amount of the wave carries is the amplitude. a.air b.nodes c.speed d.energy

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

Suppose that sociologists and cultural anthropologists are tying to measure the amount of child abuse for cross cultural comparison. they run into disagreement over whether spanking a child is abuse or discipline. what problem are they encountering in their research? a. reliability of the definition of abuse. b. validity of the definition of abuse. c. occam's razor about the definition of abuse. d. none of these.