The variability measures the closeness of the individual data provided. So, the most reliable sampling is the one with the lowest variability.
For this case, the question with the lowest sampling variability is question 3. Therefore, we can conclude that the answers to which of the questions are most reliable is question 3.
The equations standered form is y=-x^2/8-x/2-9/2
You have to add up the numbers to equal 39....so it's 18+12+9=39
