Georges asked five of his friends how long they studied for the last math test and what grade they received. He found a linear r
egression equation for the data to be y = 9.6x + 65.8. What does the 9.6 mean in the context of this equation? A) His friends on average studied 9.6 hours. B) If they studied 9.6 hours they would get a 0 on the test. C) They should study 9.6 hours in order to get an A on the test. Eliminate D) For every hour they studied their grade would go up 9.6 points.
Well assuming x is hours, answer D is correct. This is because we are taking amount of hours as the input and the grade they got as an output. So, assuming that every unit step means an hour, for each extra hour someone studied, they got 9.6 more points. The +65.8 means that usually someone who didn't study got a 65.8 because when x is 0 (0 hours studied), what's left is 65.8
A line with zero slope has no dependence on x. It is simply ...
... y = constant
The constant must be the same as the y-value of the point you want the line to go through. Since the point is (12, -9), the constant is -9 and the equation is ...
