Review Exercises (pp. 24-27) in Freedman, et al.:

Ch. 2: 4, 11

Review Exercises (pp. 50-55) in Freedman, et al.:

Ch. 3: 7, 12

Additional problems:

1. In a study of the effects of lead exposure on cognitive functioning, Dr. David Bellinger followed 170 children from middle- and upper-middle-class families in Boston. Dr. Bellinger and his colleagues found significant signs of lasting brain damage in children from low-risk environments. For every 10 micrograms of blood lead above the 10-microgram danger level measured when the children were 2 years old, there was a 5.8 decline in overall I.Q. and an 8.9 point decline in achievement scores by age 10.

a) Was this study a correlational or experimental design? Explain.

b) What is the independent variable?

c) What are the dependent variables?

d) If it were found that all of the children with higher lead levels all lived in the same neighborhood, what are some of the possible confounding variables to be concerned about?

Note: Explain your answers for the above questions.