A test has __________ validity if the researcher is able to control all extraneous variables so that the only variable influencing the results of the study is the independent variable

Mothers of infants with failure to thrive have been found to be ____ than mothers of infants without failure to thrive

a. more insecurely attached b. lower in self-esteem c. older d. less intelligent

Currently, __________% of births in the United States are to single mothers;more than __________% of African American children are born to a single mother

a) 20; 50 b) 30; 60 c) 40; 70 d) 50; 80