Answer:
Stress Level in mother's lives and surrounding people's (family, peer) addictive habits : could be lurking variables between smoking during pregnancy and children’s later test scores.
Step-by-step explanation:
Regression is a statistical tool that establishes relationship between independent (causal) variable(s) & dependent (effected) variables.
Lurking Variable is a variable which seems to effect both independent variables, and also defines the relationship between them.
Given Case : Smoking during pregnancy is the independent variable, affecting the dependent variable i.e test scores of children.
Lurking Variables (affecting both mothers' smoking, children's score & their relationship) in this case could be :
- Stress Level in mother's lives : As it effects both the mother's additive habits (smoking); & also the the mental growth of baby.
- Surrounding people's addictive habits : As it effects the mother's addictive habits (smoking) ; & also the ambience around mother, mental growth of baby.