Math , modelling , needed help ?

Question

HAVE BEEN GIVEN A TABLE WHICH SHOWS THE MEDIAN "B.M.I" (BODY MASS INDEX) FOR FEMALES OF DIFFERENT AGES IN THE U.S IN THE YEAR 2000 . THE QUESTION IS USE TECHNOLOGY TO PLOT THE DATA POINTS ON A GRAPH?? . DEFINE ALL VARIABLES USED AND STATE ANY PARAMETERS CLEARLY??what type of function models the behavior of the graph? explain why one chose this function?

AGE B.M.I

2 16.40

3 15.70

4 15.30

5 15.20

6 15.21

7 15.40

8 15.80

9 16.30

10 16.80

11 17.50

12 18.18

13 18.70

14 19.36

15 19.88

16 20.40

17 20.85

18 21.22

19 21.60

20 21.65

i know that a sin function can be used , but i do not know the reason behind it and the parametres and variables of this . my sin function is simnilar to the graph. thanks guys

Answer 1

I put the numbers in a table in Excel (two columns).

Then a created a scatter plot (x,y) of the values.

Finally I added a trendline (polynomial, order 3) and told it to display the function.

It came out with this for a "best fit"

y = -0.0041x^3 + 0.1536x^2 - 1.2757x + 18.273

I chose a 3rd order polynomial because I suspect there is a dip when you are younger, and perhaps when you are older, but I don't think it oscillates in a perfect pattern like a sin wave.