Question

Hurricane damage: In August and September 2005, Hurricanes Katrina and Rita caused extraordinary flooding in New Orleans, Louisiana. Many homes were severely damaged or destroyed, and of those that survived, many required extensive cleaning. It was thought that cleaning of flood–damaged homes might present a health hazard due to the large amounts of mold present in many of the homes. In a sample of 367 residents of Orleans Parish who had participated in cleaning of one or more homes, 81 had experienced symptoms of wheezing, and in a sample of 175 residents who had not participated in cleaning, 21 reported wheezing symptoms (numbers read from a graph). Can you conclude that there is a difference between the proportion of residents with wheezing symptoms who cleaned flood–damaged homes and those who did not participate in the cleaning?

Let p1 denote the proportion of residents with wheezing symptoms who had cleaned flood–damaged homes, and let p2 be the population proportion with wheezing symptoms who did not participate in the cleaning of flood–damaged homes. Use the α=0.01 level of significance and the critical value method.

a.) State H0 and H1

b.) Choose a significance level α and find the critical value.

c.) Compute the test statistic.

d.) Determine whether to reject H0.

e.) State a conclusion.

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Answer 1