Which of the following is a reason why maternal mortality has decreased during labor in developed countries? Improvements in _____

A representative sample is one that

a. contains every possible score on the dependent variable. b. accurately reflect the characteristics of the population. c. is based on a systematic selection of participants. d. is also known as a biased sample.

The statement "Class absences are associated with lower grades" is an example of a(n):

A) correlation. B) causal relationship. C) normal distribution. D) experiment.