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I have a homework question. I have solved most of it already, but am unsure how to proceed with one specific part that involves prediction (Parts B & C). I am not looking for anyone to just give me an answer, but was hoping someone might point me in the right direction of how I might solve this part of the question. If this isn't the appropriate place to seek this type of assistance, I apologize.

This is what I have done so far:

A sales manager wishes to examine the relationship between the numbers of miles her sales representatives travel and the amount of their monthly sales. She wishes to use this information to formulate an equation that she will use to predict Sales (y- or dependent variable, dollars) based on MilesTraveled (x- or independent variable). The following information was collected:

Miles Traveled:   50,   120,   200,   250,   300  
Sales:          2500, 10000, 15000, 17500, 21000

a) Write the equation of the regression line:

$\quad$ y = 101.695 + 71.186x

b) Predict Sales for a person traveling 150 miles:

c) Predict Sales for a person traveling 205 miles:

d) What is value of the Pearson correlation coefficient?

$\quad$ r= 0.9903, p = .001

e) Briefly define regression:

$\quad$ Regression attempts to describe the dependence of a variable on one (or more) explanatory variables.

f) Explain what the slope of 71.186 represents:

$\quad$ 71.186 represents the average change that occurred in the dependent variable (sales).

g) Explain what the y-intercept of 101.695 represents:

$\quad$ 101.695 is the point where the regression line intersects the y-axis.

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    $\begingroup$ Is this a homework question? If so, you might want a less technically correct answer (I'm thinking linear regression, but there are probably better reference distributions to use)...If not, do you have any more data than these? The prediction probably won't be very accurate in either case, unless you do have plenty more data. $\endgroup$
    – Nick Stauner
    Apr 21, 2014 at 0:36
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    $\begingroup$ (1) not sure if f is correct (2) for b, why don't you substitute x (150 miles) into the equation you have (y=101.695+71.186x) to get predicted value of y? $\endgroup$
    – charles
    Apr 21, 2014 at 1:26
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    $\begingroup$ Thanks for updating your question, @Anonymous. I no longer see any grounds for closing. $\endgroup$
    – gung - Reinstate Monica
    Apr 21, 2014 at 1:27
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    $\begingroup$ I wonder if you can say something more specific about g. I suppose it is technically right, but I suspect it isn't exactly what they're looking for. What does it mean for something to be "the point where the regression line intersects the y-axis"? What kind of point is it? What are the coordinates at that point? $\endgroup$
    – gung - Reinstate Monica
    Apr 21, 2014 at 1:32
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    $\begingroup$ Gung...thank you! That's very helpful. I totally appreciate everyone's help. I'm taking my first statistics class online so sometimes it's hard to really get one on one assistance. Thanks again! :) $\endgroup$
    – Anonymous
    Apr 21, 2014 at 1:41

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