Answer Happy

15pt] Question 3. Lead poisoning can damage a child's brain and nervous system. Assume that a study collects blood lead levels from children aged 4 and 5 years. Let X denote the age of a randomly selected child in this study and Y denote 1 if the child's blood lead level is less than 3 micrograms per deciliter (mg/dL), 2 if the child's blood lead level is between 3 and 5 mg/dL (inclusive), and 3 if the child's blood lead level is greater than 5 ug/dL. The following table shows the joint probability mass function of X and Y: y 2 1 3 I 0.05 4 5 0.1 0.2 0.2 0.4 0.05 Find the correlation coefficient of X and Y.