These graphs show the amount of lead in the air and the amount of violent
crime over several decades. when was the violent crime rate highest in each
city?
studies of the relationship of violent behavior to level of
lead in the air
chicago
san diego
atlanta
new orleans
&
a
s
1992
1972
02
982
2919
2012
2002
2012
natural log of aggravated assault rate
-
- natural log of atmospheric pb
o
o
o
a. at random times, regardless of lead level
b. when the lead level was highest
c. when the lead level was lowest
o
d. in the mid-1970s, regardless of city