Each child in a sample of 61 low-income children was administered a language and communication exam. The sentence complexity scores had a mean of 7.64 and a standard deviation of 8.92.

Requirements:

1. From the sample, estimate the true mean sentence complexity score of all low-income children.

2. Form a 90% confidence interval for the estimate, part a. The 90% confidence interval is (__, __).

3. Give a practical interpretation of the interval:

a. We are 90% confident that the mean sentence complexity score of all low-income children is outside the confidence interval.

b. We are 10% confident that the mean sentence complexity score of all low-income children is between the endpoints of the confidence interval.

c. We are 10% confident that the mean sentence complexity score of all low-income children is outside the confidence interval.

d. We are 90% confident that the mean sentence complexity score of all low-income children is between the endpoints of the confidence interval.

e. An interpretation cannot be determined.

4. Suppose the true mean sentence complexity score of middle-income children is known to be 15.55. Is there evidence that the true mean for low-income children differs from 15.55?

No

Yes

Answer rating: 100% (QA)

1 Let x denotes the sample mean of complexity scores an... View the full answer