7.49. A study1

"' compared substance use, delinquency, psychological well-being, and socialsupport among various family types,for a sample ofurban AfricanAmerican adolescent males. The sample contained 108 subjects from single-mother households and 44 from households with both biological parents. The youthsresponded to a battery ofquestionsthat provides a measure of perceived parental support. This measure had sample means of 46 (,v = 9) for the single-mother households and 42 (.9 = 10) for the households with both biological parents. Consider the conclusion, "The mean parental support was 4 units higher for the single-mother households. If the true means were equal, a difference of this size could be expected only 2% of the time. For samples of this size, 95% of the time one would expect this difference to be within 3.4 of the true value."

(a) Explain how this conclusion refers to the results of (i) a confidence interval, (ii) a test.

(b) Describe how you would explain the results of the study to someone who has not studied inferential statistics.