10.87 Parental support and household type A recent study interviewed youths with a battery of questions that provides a summary measure of perceived parental support.

This measure had sample means of 46 1s = 92 for the single-mother households and 42 1s = 102 for the households with both biological parents. One conclusion in the study stated, “The mean parental support was 4 units higher for the single-mother households. If the true means were equal, a difference of at least 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.” Explain how this conclusion refers to the results of

(a) a confidence interval and

(b) a significance test.