The graph shows the average monthly high temperature in Newark NJ for months from November to April. If a quadratic model is fit to the graphed data set will a be positive or negative?
A) positive
B) negative

Question

The graph shows the average monthly high temperature in Newark NJ for months from November to April. If a quadratic model  is fit to the graphed data set will a be positive or negative? 
A) positive 
B) negative

Quizplus · Accepted Answer

A quadratic equation in the form of y = ax^2 + bx + c has a positive "a" coefficient if it opens upwards (like a smiley face). Since the graph of the average monthly high temperature in Newark NJ has a concave upwards shape, the quadratic model will have a positive "a" coefficient. Therefore, the answer is A (positive).

The Graph Shows the Average Monthly High Temperature in Newark