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Homework Help: Regression/deviation please help

  1. Jun 22, 2011 #1
    1. The problem statement, all variables and given/known data
    Data were obtained on watermelon plants; variables of interest were the depth of the roots (inches) and the weight of the watermelon (ounces). A total of 100 plants were measured, with the following summary results: depth mean = 16, weight mean = 75, depth standard deviation = 8, weight standard deviation = 20, and correlation = 0.68. Assume that the relationship is linear. [10 points total]

    a. Describe the relationship’s direction and strength. [2 points]
    b. Determine the value for the slope of the least squares regression line for predicting weight.
    c. Determine the value for the intercept of this least squares regression line.
    d. State this regression equation.
    e. When the roots are 20 inches deep, predict the watermelon weight.
    f. One of the data points was depth = 20, weight = 86. Find the residual for this point.
    g. Give the coordinates for two points that are on the regression line. [2 points]
    h. If we formed the regression equation to predict root depth, would the resulting regression line have the same slope? (Yes or No)

    2. Relevant equations I THINK I know a variety of the equations I have to use, for I usually am given a data table to work with. Please help, the wording is very confusing and I have been on this question for two hours.

    3. The attempt at a solution

    the direction is positive for a. and I am not sure about it's strength but I do know it is 68%
    b = a (sy/sx) for b.?
    For number c. I understand I have to find b but I am not sure how due to the wording

    I think h. is yes but I am not sure :/

    Please help me!:(
    Last edited: Jun 22, 2011
  2. jcsd
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