Answer:
Parents' income
Step-by-step explanation:
The confounding variable also called the third or lurking variable is usually an unaccounted for variable or factor which may creep into our research, Hence, causing an association or relationship which does not actually exists between the two correlated variables. In the experiment abive, there is no really any actual relationship between increasing percentage of free lunch and less usage of bicycle helmets.
However, We may attribute the change in bicycle helmets used by the children to a swerve or change in the income of the parents of the students, being able to afford a bicycle helmet will depend in the income of the parent and this mightvhave caused the observed association between the variables.
