Sentence complexity study. A study published in Applied Psycholinguistics (June 1998) compared the language skills of young children (16–30 months old) from low-income and middle-income families. A total of 260 children—65 in the low-income and 195 in the middle-income group—

completed the Communicative Development Inventory

(CDI) exam. One of the variables measured on each child was sentence complexity score. Summary statistics for the scores of the two groups are reproduced in the accompanying table. Use this information to sketch a graph of the sentence complexity score distribution for each income group. (Assume that the distributions are mound shaped and symmetric.) Compare the distributions. What can you infer?

Low Income Middle Income Sample Size 65 195 Mean 7.62 15.55 Standard Deviation 8.91 12.24 Minimum 0 0 Maximum 36 37