Please help me I need to input specific X and Y values into a list in my TI89+ and later find a cubic function

Question

Ex: I'm trying to input these x and y values on my calculator to find a cubic function to represent the data.
X: 3, 5, 7, 8, 10, 12, 15
Y: 2.0, 4.2, 8.8, 11.1, 13.8, 16.0, 17.7

(How may I do this? Step by step walkthrough will be greatly appreciated =D)

As I said before I want to input these values into a list and then use the CobicReg option. Since this is also my first time using a TI89+TITANIUM, I also want to learn how to input X and Y values to find linear, quadratic, and cubic functions, so on and so forth.

Answer 1

Is there no manual?☺