Reference no: EM131818220
"Environmental Mercury, Autism Linked by New Research" reported in Environmental News Service in March 2005 that Texas researchers had found a possible link between autism and mercury in the air and water. "The study compared mercury totals reported for 2001 in the 254 Texas counties to the rate of autism and special education services in nearly 1,200 Texas school districts. The districts, which range from urban to small metro to rural, enroll 4 million Texas children. 'The main finding is that for every 1,000 pounds of environmentally released mercury, we saw a 17 percent increase in autism rates,' said lead author Raymond Palmer, Ph.D., associate professor in the Health Science Center's department of family and community medicine."11
a. Were the individuals studied best described as Texas counties, Texas school districts, or Texas children?
b. Describe the two quantitative variables of interest, and tell which is explanatory and which is response.
c. Is the slope of the regression line 1,000/0.17 or 0.17/1,000?
d. Should researchers denote the slope for their findings as b0, b1, b0, or b1?
e. Since the study produced evidence of a relationship, can we conclude that a 95% confidence interval for b1 contains zero?
f. Considering that the sample size was quite large, was the P-value probably much greater than 0.05, approximately 0.05, or much less than 0.05?
g. Which one of these possible confounding variables would have been most important for the researchers to take into account: setting as urban, small metro, or rural; gender; time of year; age of children?