Need Help with quadratic regression

Question

Explain the real-world meaning of the parameters a, b, and c of the quadratic function model.
Based on data from 1990 to 2003, the amount of money spent on prescription drugs (per capita) can be modeled by
P(t) = 2.889t2 − 2.613t + 158.7
dollars, where t is the number of years since 1990.†
The parameter "a" 2.889. and represents the rate at which the amount of money spent on prescription drugs per year is increasing, which is ????? dollars per year. The parameter "b" is  -2.613 and represents the decrease in the amount of money spent on prescription drugs per year in the initial year of 1990 . The parameter "c" is 158.7 and represents the amount of money spent on prescription drugs in 1990

 

Need help with the dollar amount each year

Answer 1

The problem tells you that "t" represents the number of years SINCE 1990. If it helps, you can simply think of P(t) as being the same thing as y. If you plug in a value for t, what are you going to get for y? For example, if we plug in 2 for t (which means the year 1992 because t = the number of years after 1990) you end up making $165.03. I've shown you some of of the calculations below. I'm sure you can figure out the rest. As you can see, this pharmaceutical company is making more and more each year. THAT DEFINITELY APPLIES TO THE REAL WORLD! 

 

P(1) = (2.889)(1^2) - (2.613)(1) + 158.7 = $158.98 in 1991

 

P(2) = (2.889)(2^2) - (2.613)(2) + 158.7 = $165.03 in 1992 (the year I was born!)

 

P(3) = (2.889)(3^2) - (2.613)(3) + 158.7 = $176.86 in 1993

 

P(4) = (2.889)(4^2) - (2.613)(4) + 158.7 = $194.47 in 1994

 

P(5) = (2.889)(5^2) - (2.613)(5) + 158.7 = $217.86 in 1995