171k views
0 votes
McDonald's Corporation has reported the following values for total revenues and net income during the 1998 to 2005 period. All data are in billions of dollars: Source: McDonald's Corporation, 2005 Annual Report. 1998 1999 2000 2001 Net Income 1.55 1.95 1.98 1.64Total Revenues 12.42 13.26 14.24 14.87 2002 2003 2004 2005 Net Income 0.89 1.47 2.28 2.60Total Revenues 15.41 17.14 19.07 20.46 Determine the least-squares regression equation line for estimating net income and interpret its slope.

User Edumelzer
by
5.5k points

1 Answer

4 votes

Answer:


y=0.0998 x +0.212

For this case the slope means that for every increase of 1 unit in the Revenues we will have an increase of approximately 0.0998 in the net income.

We assume that Net Income (Y) and the Revenues represent (X)

See explanation below.

Explanation:

For this case w ehave the following data:

Year 1998 1999 2000 2001 2002 2003 2004 2005

Net Income 1.55 1.95 1.98 1.64 0.89 1.47 2.28 2.6

Revenues 12.42 13.26 14.24 14.87 15.41 17.14 19.07 20.46

We assume that Net Income (Y) and the Revenues represent (X)

For this case we need to calculate the slope with the following formula:


m=(S_(xy))/(S_(xx))

Where:


S_(xy)=\sum_(i=1)^n x_i y_i -((\sum_(i=1)^n x_i)(\sum_(i=1)^n y_i))/(n)


S_(xx)=\sum_(i=1)^n x^2_i -((\sum_(i=1)^n x_i)^2)/(n)

So we can find the sums like this:


\sum_(i=1)^n x_i =126.87


\sum_(i=1)^n y_i =14.36


\sum_(i=1)^n x^2_i =2067.503


\sum_(i=1)^n y^2_i =27.7264


\sum_(i=1)^n x_i y_i =233.2763

With these we can find the sums:


S_(xx)=\sum_(i=1)^n x^2_i -((\sum_(i=1)^n x_i)^2)/(n)=2067.503-(126.87^2)/(8)=55.503


S_(xy)=\sum_(i=1)^n x_i y_i -((\sum_(i=1)^n x_i)(\sum_(i=1)^n y_i))/(n)=233.2763-(126.87*14.36)/(8)=5.544

And the slope would be:


m=(5.544)/(55.503)=0.0998

Nowe we can find the means for x and y like this:


\bar x= (\sum x_i)/(n)=(126.87)/(8)=15.859


\bar y= (\sum y_i)/(n)=(14.36)/(8)=1.795

And we can find the intercept using this:


b=\bar y -m \bar x=1.795-(0.0998*15.859)=0.212

So the line would be given by:


y=0.0998 x +0.212

For this case the slope means that for every increase of 1 unit in the Revenues we will have an increase of approximately 0.0998 in the net income.

User Hituptony
by
5.3k points
Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.