2. In an effort to determinewhether exposure to high lead levels has an effect o
ID: 2917237 • Letter: 2
Question
2. In an effort to determinewhether exposure to high lead levels has an effect on bloodpressure in young children, blood-pressure measurements were takenon 30 children aged 5-6 years living in a specific communityexposed to high lead levels. For these children, the meandiastolic blood pressure was found to be 66.2 mm Hg with standarddeviation 7.9 mm Hg. From a nationwide study, we know thatthe mean diastolic blood pressure is 58.2 mm Hg for 5- to 6-yearold children. We will assume that exposure to lead will haveeither no effect or cause an increase in bloodpressure.
a) Determine aone-sided 95% confidence interval for diastolicblood pressure among 5- to 6-year-old children in this communitybased on the observed 30 children. Based on this confidenceinterval, does it appear that children who are exposed to lead havehigher blood pressure?
b) As wediscussed in class, we can either compute confidence intervals orconduct a hypothesis test to evaluate the relationship between leadand blood pressure. Now, conduct the appropriate hypothesistest at the = 0.05 level to determine whether lead causes anincrease in blood pressure.
c) Doesthe conclusion from this test agree with the findings from part a)where you computed the one-sided 95% confidence interval? Whyor why not?
Explanation / Answer
n=30, X-bar=66.2, S=7.9 =0.05, Z0.05=1.645 (a) The one-sided 95% confidence interval isX-bar+1.645*S/n=66.2+1.645*7.9/30=68.572 Based on this confidence interval, it appears that children who areexposed to lead have higher blood pressure. (b)Ho:58.2 The test statistics isZ=(X-bar-)/(S/n)=(66.2-58.2)/(7.9/30)=5.55 Since Z=5.55>1.645, reject Ho. (c)Yes, the conclusion from this test agree with the findings frompart a) where you computed the one-sided 95% confidenceinterval.Related Questions
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