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Mathematical Modeling, watch

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    Hi, im doing a project in which we must find an equation that best fits the data we were given.

    When I applied a polynomial function where the highest degree was 3, the Correlation Coefficient was equal to .9991. However, when I applied a polynomial function where the highest degree was 5, the correlation coefficient was equal to .9996.

    Is there a reason why a function with a higher degree models the data better than one of a lower degree?
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    (Original post by nk9230)
    Hi, im doing a project in which we must find an equation that best fits the data we were given.

    When I applied a polynomial function where the highest degree was 3, the Correlation Coefficient was equal to .9991. However, when I applied a polynomial function where the highest degree was 5, the correlation coefficient was equal to .9996.

    Is there a reason why a function with a higher degree models the data better than one of a lower degree?

    Which data is it?
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    (Original post by motoroller)
    Which data is it?
    *EDIT*
    It is Body Mass Index for Females from a particular year in the United States.

    I first tried a Cubic, and then a Quintic.
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    (Original post by nk9230)
    cubic
    Trends probably can't be analysed mathematically. What reason would there be for the BMI to follow a cubic or quintic? In some physical situation like fluid flow, there might be an underlying cubic flow rate, but I don't think there is significance in data like this. All you can do is comment on the patterns observed from the data.
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    (Original post by motoroller)
    Trends probably can't be analysed mathematically. What reason would there be for the BMI to follow a cubic or quintic? In some physical situation like fluid flow, there might be an underlying cubic flow rate, but I don't think there is significance in data like this. All you can do is comment on the patterns observed from the data.
    Well, there has to be a funtion to model the data that was given to us, Its an IB Maths IA type II. I used a cubic based on the shape/ trend the data followed when plotted as a scatter plot.
 
 
 
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