SOLUTION: In need of assistance please, as I am completely lost. I was hoping to receive help understanding the following question: A regression was run to determine whether there is a

Algebra ->  Statistics  -> Scatterplots-graphs -> SOLUTION: In need of assistance please, as I am completely lost. I was hoping to receive help understanding the following question: A regression was run to determine whether there is a      Log On


   



Question 1127750: In need of assistance please, as I am completely lost.
I was hoping to receive help understanding the following question:
A regression was run to determine whether there is a relationship between hours of TV watched per day(x)and number of sit-ups a person can do (y). The results of the regression are given below. Use this to predict the number of sit-ups a person who watches 11 hours of TV can do.
y=ax+b
a=−1.341
b=32.234
r=−0.896
What is really throwing me off is where "r" comes into play.
I am not simply seeking an answer, instead I am asking for your knowledge on how to understand this type of equation, and how to solve something such as this.
Thank you for your time!

Found 2 solutions by MathLover1, MathTherapy:
Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!
x=hours of TV watched per day
y number of sit-ups a person can do

y=ax%2Bb
if given:
x=11h
a=-1.341
b=32.234
y=-1.341%2A11%2B32.234
y=17.483


You actually do not need r to find y. Also, when they say "use this", their meaning is "use this formula".
y+=+ax+%2B+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,for example, 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?

why r=-0.896?
We should compute the correlation coefficient only for data that follows a linear pattern or to determine the degree to which a data set is linear.
If the data exhibits a nonlinear pattern, the correlation coefficient for a linear regression is meaningless.
To get a sense for the relationship between the value of +r and the graph of the data.
The correlation coefficient is a value, +r , between -1 and 1.
r%3E0 suggests a positive (increasing) relationship
r%3C0+ suggests a negative (decreasing) relationship
The closer the value is to 0, the more scattered the data.
The closer the value is to 1 or -1, the less+scattered the data is.
You have r=-0.896. This value is very close to -1, which suggests a strong decreasing+linear relationship and the data is less+scattered.

Answer by MathTherapy(10551) About Me  (Show Source):
You can put this solution on YOUR website!

In need of assistance please, as I am completely lost.
I was hoping to receive help understanding the following question:
A regression was run to determine whether there is a relationship between hours of TV watched per day(x)and number of sit-ups a person can do (y). The results of the regression are given below. Use this to predict the number of sit-ups a person who watches 11 hours of TV can do.
y=ax+b
a=−1.341
b=32.234
r=−0.896
What is really throwing me off is where "r" comes into play.
I am not simply seeking an answer, instead I am asking for your knowledge on how to understand this type of equation, and how to solve something such as this.
Thank you for your time!
r is GIVEN and is needed to determine if there's a relationship/correlation between the 2 variables. 
Since there is a correlation between the variables, the regression equation can be used to predict the dependent or y variable. If there was no
relationship/correlation between the 2 variables, then you would NOT be able to use the regression equation to predict the number of sit-ups
a person can do, or y. In that case, the mean of the dependent variable would be the BEST predictor of y, or the number of sit-ups a person can do.