In: Statistics and Probability
A study was conducted to investigate the hypothesis that living within 100 meters of a large highway increased the risk of childhood respiratory illness. The investigators recruited 200 children ages 6 to 10 years old living near highways and another 200 children of similar age, gender and ethnicity living more than 100 meters from highways. They followed the children for 3 months and asked the parents to record in a daily diary any symptoms of respiratory illness. At the end of the 3 months, 36 of the 200 “exposed” children (living near a highway) had developed at least one respiratory illness, while 17 of the 200 living further away had developed respiratory illness. a. What kind of study was this? b. What measure of disease frequency can be calculated? Calculate it for each group and interpret the results. c. What measure of association can be calculated? Calculate it and interpret the results.