Maths Portfolio - SL TYPE II BMI

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                SL TYPE II BMI

Body Mass Index

Body mass index is a measure of one’s body fat. It is calculated by taking one’s weight(kg) and dividing by the square of one’s height(m).

The table(Figure 1.0) below gives the median BMI for females from the range of 2 years old to 20 years old in the US, in the year 2000.

Figure 1.0

In this investigation I will examine a variety of functions to mathematically predict the fluctuations for the ‘average’ American female’s body mass index. The parameters that are used in this graph are the Age which is represented in years and will be the X-Axis on the graph, and the BMI(Body Mass Index) which is given to 4 significant figures and will be placed on the Y-Axis. Although not listed, there are a variety of variables that can affect one’s BMI the most common ones being race, genetics, eating habits and environmental factors/variables.

Figure 1.1 Here is the graph, with the data points from the table above.

Figure 1.2 Here is the graph with the points joined up.

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By observing the nature of the curve it is possible to deduce the function that models the graph. From Figure 1.2 we can observe that the graph is clearly not linear, since it is not straight. It is not exponential or a quadratic either since we can examine the curve growing and then declining towards the end of the graph. Therefore the only function models suitable enough for the graph are Cubic, Quartic, Quintic, Sine and Gaussian.

I have chosen the Quintic function because it fits the data points of Graph 1.1 relatively closely, therefore making it a rather ...

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