Statistics - Correlation Coefficient/Regression

posted by .

'm having some difficulty with the following question:

The following data shows expenditures (in millions of dollars) and case (sales in millions) for 7 major soft drink brands. Calculate the correlation coefficient. Is this significant at the 5% level (ie, α=.05)? Construct the regression equation for this data. Decide how much RC Cola would make if they spend 643.8. Do the same for Canada Dry if they spend 13.8. Is it a good idea to use this regression equation for RC and Canada Dry? Why?

Brand Spending Sales
Coke 131.3 1929.2
Pepsi 92.4 1384.6
Diet Coke 60.4 811.4
Sprite 55.7 541.5
Dr Pepper 40.2 536.9
Mt Dew 29.0 535.6
7-Up 11.6 219.5
I made my table & came up with:

I'm having trouble getting the correlation coefficient. I used the formula in my textbook:

r=nΣxy-(Σx)( Σy) / √n(Σx²)-(Σx)² * √n(Σy²)-(Σy)²

but I keep coming up with different answers (I've done it by hand & with my TI-84 plus (LinRegTTest) several times each). I've figured out b1 (14.42378282) for the slope equation but for b0, my answer keeps changing (I get -15.something & the "something" is what keeps changing every time I work the problem out).

Please help!

  • Statistics - Correlation Coefficient/Regression -

    I used an online calculator and came up with this:

    y = a + bx where:
    a= -15.4
    b= 14.4

    r = 0.978

    Your formula looks correct. It's easy to make errors with the calculations when doing these kinds of problems.

  • Statistics - Correlation Coefficient/Regression -

    y = -15.4 + 14.4x
    the correlation coefficient is correct because it is geomatric mean of two regression coefficient the second regression coefficient is 0.066428.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. statistics

    3. The following data shows expenditures (in millions of dollars) and case (sales in millions) for seven major soft drink brands. Show a scatter diagram of the data and describe in words what it tells you. Calculate the correlation …
  2. Statistics 15.59

    Computer database GROWCO describes the characterisitics of 100 companies identified by Fortune as the fastest growing. Two of the variables listed are revenue and net income (millions of dollars) for the most recent four quarters. …
  3. statistics

    Given the following scatter diagram , the sample correlation coefficient r: Has a positive linear correlation Has a negative linear correlation. Has little or no correlation. Looks close to + 1.00

    A) If a regression experiment has correlation coefficient r= 0.75, what precent of total variation is explained by the regression?
  5. statistics

    If the correlation coefficient is -0.54, what is the sign of the slope of the regression line?
  6. Finance

    Use the following information to calculate the covariance of asset A with an equally weighted portfolio of assets B and C. Asset Standard Deviation A 20% B 30% C 40% The correlation coefficient between A and B is 0.6. The correlation …
  7. statistics

    how do I find the correlation coefficient r?
  8. Statistics

    5. For the data presented below, answer the questions that follow. Score on political Score on current Individual awareness test events test 1 24 23 2 16 12 3 11 11 4 9 6 5 8 13 6 14 11 7 17 16 8 19 16 9 21 21 10 25 25 11 18 11 12 …
  9. statistics

    Construct a scatterplot. b. Draw a regression line through the data point that “fits” the data points reasonably well. c. Enclose the data points with a ellipse. d. Estimate the direction of the correlation. e. Estimate the strength …
  10. Statistics

    The correlation coefficient between X and Y is the same as the correlation coefficient between Y and X. True - If you were to find the correlation coefficient with a given data set for x and y, it would have the same correlation coefficient …

More Similar Questions