Sentence complexity study. Refer to the Applied Psycholinguistics (June 1998) study of lan...

Sentence complexity study. Refer to the Applied Psycholinguistics (June 1998) study of language skills of low-income children, presented in Exercise 2.98 (p. 74). Each in a sample of 65 low-income children was administered the Communicative Development Inventory (CDI) exam. The sentence complexity scores had a mean of 7.62 and a standard deviation of 8.91.

a. Construct a 90% confidence interval for the mean sentence complexity score of all low-income children.

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b. Interpret the interval you found in part a in the words of the problem.

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c. Suppose we know that the true mean sentence complexity score of middle-income children is 15.55. Is there evidence that the true mean for low-income children differs from 15.55? Explain.

Exercise 2.98