How to predict something based on its regression?

A regression was run to determine if there is a relationship between hours of TV watched per day (x) and number of situps a person can do (y).

The results of the regression were:
y=ax+b a=-1.298 b=34.871 r²=0.544644 r=-0.738

Use this to predict the number of situps a person who watches 13 hours of TV can do (to one decimal place)
______?


How do I even start this?

Start by making sure that you understand all of the symbols.

Symbols x and y each represent numbers that vary. Symbols a and b represent numbers that remain fixed (constants).

For example, if I say that x=9 for you and that x=2 for me, what is the meaning of that statement, actually?




Also, when they say "use this", their meaning is "use this formula".

y = ax + b

That's a formula for some variable y. In other words, if you know what x is, then you can find its associated value of y. But, what does y represent? If I told you that y=27.5 when x = 5.7, what is the meaning?




They gave you the values of the constants a and b.

Anytime you're given the value of a constant, you may substitute the given value for the symbol anywhere that symbol appears.




Finally, they gave you a value for x. They want to know what will y be for that value of x?

I did the plugging in thing and got 40.9 which seems to be wrong.

DasRabbit said:

I did the plugging in thing

Click to expand...

I am unable to help you with your plugging in thing.

I am able to help people who show me their work. :cool:

Your intuition is good, however; 40.9 is not correct.