Approximately what proportion of adults in North America become stepparents, foster parents, or adoptive parents?

Linda's 3-month-old infant keeps saying "ga-ga" and "doh-doh." Should she be worried?

A) Yes; parents should not encourage nonsense language in their infants, because it can lead to language problems later on. B) Maybe; her 3-month-old should be saying at least a couple of words by now. C) No; this behavior is called babbling and it is normal for infants. D) No, although the infant should start to string these syllables together to form words in the next month or two.

What are the values for SS and variance for the following sample of n = 4 scores? Sample: 1, 1, 0, 4

a. SS = 9 and variance = 3 c. SS = 18 and variance = 6 b. SS = 9 and variance = 2.25 d. SS = 18 and variance = 9