# Question: The authors of the paper Decreased Brain Volume in Adults

The authors of the paper “Decreased Brain Volume in Adults with Childhood Lead Exposure” (Public Library of Science Medicine [May 27, 2008]: e112) studied the relationship between childhood environmental lead exposure and a measure of brain volume change in a particular region of the brain. Data were given for x = mean childhood blood lead level (mg/dL) and y = brain volume change (BVC, in percent). A subset of data read from a graph that appeared in the paper was used to produce the accompanying Minitab output.

Carry out a hypothesis test to decide if there is convincing evidence of a useful linear relationship between x and y. Assume that the basic assumptions of the simple linear regression model are reasonably met.

Carry out a hypothesis test to decide if there is convincing evidence of a useful linear relationship between x and y. Assume that the basic assumptions of the simple linear regression model are reasonably met.

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