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Math Help - Sorry! This one...thanks

  1. #1
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    Sorry! This one...thanks

    Year Average Poverty Threshold (in $)
    1965 3022
    1970 3223
    1975 3968
    1980 5500
    1985 8414


    A.) Find a model for this data


    B.) Estimate the average poverty threshold for a family of four in 1990


    C.) Give a reasonable Domain and Range
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  2. #2
    Eater of Worlds
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    Excel does regressions. Do you have Excel?.

    Let t=0 be 1965

    A quadratic regression works pretty well.

    y=17.751x^{2}-93.809x+3100.8

    R^{2}=0.9964
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  3. #3
    A riddle wrapped in an enigma
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    Quote Originally Posted by ep78 View Post
    Year Average Poverty Threshold (in $)
    1965 3022
    1970 3223
    1975 3968
    1980 5500
    1985 8414


    A.) Find a model for this data


    B.) Estimate the average poverty threshold for a family of four in 1990


    C.) Give a reasonable Domain and Range
    Graph a scatter plot of your data. Let x-axis be the year and y-axis the $

    Plots looks to be quadratic.

    17.75142857x^2-69856.92286x+68729694.4=0 with a coefficient of determination to be .9964

    Estimate the average poverty threshold for a family of four in 1990: $11,850.20

    This regression was done on a TI-84+
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  4. #4
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    sorry i have another question..i am just confused on how you got the model...could you please explain?

    Quote Originally Posted by masters View Post
    Graph a scatter plot of your data. Let x-axis be the year and y-axis the $

    Plots looks to be quadratic.

    17.75142857x^2-69856.92286x+68729694.4=0 with a coefficient of determination to be .9964

    Estimate the average poverty threshold for a family of four in 1990: $11,850.20

    This regression was done on a TI-84+
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  5. #5
    A riddle wrapped in an enigma
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    Quote Originally Posted by ep78 View Post
    sorry i have another question..i am just confused on how you got the model...could you please explain?
    What tools do you have at your disposal? Galactus said he used Excel from Microsoft Office. I've never used Excel for that before. Maybe Galactus can elaborate.

    Of course, the long way would be the algebraic, paper, pencil way.

    I used a TI-84+ calculator to plot the data. I observed the data seemed to follow a parabolic curve. I performed a quadratic regression analysis to find the best quadratic equation that would best fit the curve. The equation I produced had a coefficient of determination of .9964. The closer this number is to 1, the better. This means the curve produced by my equation is pretty accurate.
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  6. #6
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    i got it now..thanks so much..
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