Question

I've to create a scatter plot using the following coordinates: (0,15.0), (1000,13.0), (2000,11.0), (3000,9.1) and (4000,7.1)
using these points i have to find a prediction equation. thus, i used the points (1000,13.0) and (3000,9.1) the equation i found was y = -0.00195x + 14.95. Am I doing right so far?

Answer 1

Well, I really do not get what precisely you're supposed to do. If you shall find a term of a function on whose graph the aforementioned points are located, you will have to make a LES (linear equation system).
y = ax^4+bx^3+cx^2+dx+e
Since 5 points are given, it is somewhat easy to either prove or deplore the existence of a unique solution. (Or that there doesn't even exist one at all...)

Answer 2

Well the x values represent the altitudes and the y values are the temperatures presented at each of the altitudes. Thus I've to find a prediction equation.