Question

littile question on statistics, picture below

Answer 1

can you explain that?

Answer 2

its about statistics

Answer 3

yes let me see how I want to explain it

Answer 4

The second part is asking you for the value of R^2. Sounds familiar?

Answer 5

ow ` I just have to square it ?

Answer 6

what if it asks The Buick Regal has a horsepower of 127. What is the predicted mileage for the Buick Regal?

Answer 7

i have to plug 127 into function?

Answer 8

yes

Answer 9

what about this one Predicting the value of a response variable for an individual whose x-value is out of our range of data is called

Answer 10

Then you can still use the regression line to derive an predicted value for y, given the x. However, it is likely to be less reliable for an x outside the range of x in the original sample, particularly if it is a long way outside of that range.

Answer 11

so how should I answer this question ?

Answer 12

I'm guessing just use your regression line if it asking you for an actual predicted y value

Answer 13

Im sorry, I dont get it

Answer 14

is it going to be extrapolation

Answer 15

Yes

Answer 16

I think it asking for definition of extrapolation

Answer 17

Well, that's why you have a textbook. Look it up.

Answer 18

so, my last question is What is the residual for the Chevy Malibu?

Answer 19

Residual is the difference between the predicted and actual value. So calculate the predicted value and compare it to the actual.

Answer 20

So, I have to plug 251 and 28 into fuction?

Answer 21

No. You are predicting one variable in terms of the other, using the regression line. You are predicting the value of y, given x. You are predicting the value of mileage as a function of horsepower.

That gives you the predicted value of mileage.

The residual is then the difference between this predicted number and the actual mileage.

These are fundamental concepts. I recommend you go back and re-read your lecture notes and/or the chapter in your text book to make sure you have this straight.

Answer 22

ok , got it thanks

Answer 23

I got the answer for that -2.1380

Answer 24

could you expalin this one?

Answer 25

Suppose we had instead measured mileage in kilometers per liter (1 m/g = 0.425 km/l). What would be the value of the correlation between X and Y?

Answer 26

to change from mile per gallon to km per liter you would multiply each mileage value by a conversion factor (a fixed number).
call that number a. If you plug in that factor everywhere into your formula how does it change the final correlation ?

Answer 27

satys same?

Answer 28

is it 0.8651 ?

Answer 29

yes, it stays the same. But you can prove it to yourself.

Answer 30

but when I enter the answer 0.8651 . it says , it's wrong

Answer 31

now ,its right , thank you very much