âś“&Population and the number of schools
*&Hair length and shoe size
*&Number of people who carpool to &work and money spent on gas
âś“&Hours worked and money earned
Practice makes perfect
We are given pairs of data and are asked which of them will show a positive association. Let's start with the first pair.
Population and the number of schools
As the population size increases, so does the number of young people. At some point there will be so many young people that a new school will be needed so that everyone can fit.
Therefore, as the population size increases, so does the number of schools. This means that the population and the number of schools will show a positive association.
âś“Population and the number of schools
Let's check out the next pair.
Hair length and shoe size
Hair length changes frequently — either hair is growing (increase) or it is cut (decrease). Shoe size, however, stays more or less the same. Therefore, there should not be any association between the two.
*Hair length and shoe size
Now, let's see the next pair.
&Number of people who carpool to &work and money spent on gas
Imagine that two people decided to drive to work together in one car instead of driving to work in their own cars. They would spent, in total, half the amount of money on gas.
Therefore, the more the number of people that carpool to work, the less money spent on gas. This means that the number of people who carpool and money spent on gas will show a negative association.
*&Number of people who carpool to &work and money spent on gas
Finally, let's consider the last pair.
&Hours worked and money earned
If you get paid by the hour, the more hours you work the more money you earn. This means that this relationship will show a positive association.
âś“&Hours worked and money earned
Let's summarize our results!
âś“&Population and the number of schools
*&Hair length and shoe size
*&Number of people who carpool to &work and money spent on gas
âś“&Hours worked and money earned
