In a study of inorganic arsenic (iAs) in rice, a simple random sample of 36 bags of CA brown rice were tested. The mean amount of iAs in these samples was 0. 11 ppm (parts per million) with a standard deviation of 0.043. (a) Use this data to construct a 99% confidence interval for the mean amount of inorganic arsenic in bags of brown rice from CA.
(b) Does the interval that you constructed in (a) support the CA rice grower's association claim that the mean level of inorganic arsenic in bags of brown rice from California is less than half of the federally mandated level of 0.25 ppm? Explain your answer.