# Question: A subset of data read from a graph that appeared

A subset of data read from a graph that appeared in the paper “Decreased Brain Volume in Adults with Childhood Lead Exposure” (Public Library of Science Medicine [May 27, 2008]: e112) was used to produce the following Minitab output, where x = mean childhood blood lead level (mg/dL) and y = brain volume change (percentage). (See Exercise 13.19 for a more complete description of the study described in this paper)

a. What is the equation of the estimated regression line?

b. For this dataset, n 5 100, x 5 11.5, se 5 0.032, and Sxx 5 1764. Estimate the mean brain volume change for people with a childhood blood lead level of 20 mg/dL, using a 90% confidence interval.

c. Construct a 90% prediction interval for brain volume change for a person with a childhood blood lead level of 20 mg/dL.

d. Explain the difference in interpretation of the intervals computed in Parts (b) and (c).

a. What is the equation of the estimated regression line?

b. For this dataset, n 5 100, x 5 11.5, se 5 0.032, and Sxx 5 1764. Estimate the mean brain volume change for people with a childhood blood lead level of 20 mg/dL, using a 90% confidence interval.

c. Construct a 90% prediction interval for brain volume change for a person with a childhood blood lead level of 20 mg/dL.

d. Explain the difference in interpretation of the intervals computed in Parts (b) and (c).

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