A developmental psychologist is interested in generating a model
to describe and explain changes in IQ. To do this, he has developed
a questionnaire that asks people to answer questions such that he
has a measure of their IQ. Using this questionnaire, he is curious
if participants’ cognitive abilities, as measured by the IQ scale,
will change as people grow older. In order to test this, he
collects data from a group of individuals (i.e., young adults) that
range in...