Intro

During the discussion about the new CDC guidelines beginning ~ 13:22, Pam misstated that at 30 months of age, the average boy is producing about 200 words and the average girl is producing about 300 words at 30 months. Those estimates are for 24 months. Specifically, the MacArthur-Bates Communicative Development Inventories (2nd edition) provide these values for the number of words produced by • a 24-month-old boy o at the 50th percentile = 252 o at the 10th percentile = 63 • a 24-month-old girl o at the 50th percentile = 346 o At the 10th percentile = 92 • a 30-month-old boy o at the 50th percentile = 520 o at the 10th percentile = 205 • a 30-month-old girl o at the 50th percentile = 582 o at the 10th percentile = 298