Question

Demonstrating that a correlation exists does not prove that changes in one variable are the cause of changes in the other, partly because other factors which are undetected may be influencing both known variables. Thus, knowing that a correlation exists may lead to two or more different interpretations of the correlation. For each of the studies described below, decide whether the correlation is positive or negative and give two explanations for the finding.

1 A government study reveals that the more a mother smokes, the more likely her children are to exhibit behavioral problems.

2 The more psychology courses students take during their college years, the higher their scores on a measure of interpersonal sensitivity.

3 A survey of adolescents being treated for eating disorders noted that those who watched the most TV during the week tended to receive the lowest ratings on a measure of general health.

Answer 1

we know that 2 variables are positively correlated when they both increase or decrease together

we know that 2 variables are negatively correlated when 1 variable increases the other decreases

Also note that correlation can lie between -1 to 1
values close to zero indicate weak or no correlation , keeping this in mind

1 A government study reveals that the more a mother smokes, the more likely her children are to exhibit behavioral problems.

there is a positive correlation between the 2 variables

more a mother smokes , the likelihood of behavioral problems increases

2 The more psychology courses students take during their college years, the higher their scores on a measure of interpersonal sensitivity.

there is a positive correlation between the 2 variables

more courses is directly related to higher scores . Hence they are positively correlated

3 A survey of adolescents being treated for eating disorders noted that those who watched the most TV during the week tended to receive the lowest ratings on a measure of general health.

there is a negative correlation between the 2 variables

so when adolescents watch MORE tv they recieve LOWEST ratins , hence the 2 variables move in the opposite direction