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Body Mass Index


afitz

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  • 2 weeks later...

hey can anyone help me with finding the data from another country..

well for the rest of the people out there.. i think the polynomial would be the best idea.. use ur calculator and ull get an almost perfect curve if u do a x^3 or x^4 regression...

as of now only having problem finding the data from another country..

just cant believe that we are doing task 1 and task 2 portfolio's back to back in 2 weeks.. this pressure is killing me..

but atleast now m working on schedule!!

plus i found something from bahrain but its only from age group 6-18 so does that work for the last question?

Edited by wanderer
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  • 2 weeks later...

actually..i tried to use periodic funtions but the problem is that the equation is not even in a wave form...how do we find the period?? Please help me :)

btw do u guys recommend using excel i tried mathmatica but i cudnt find a way to get rid of the line of best fit

Edited by wahyan32
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  • 2 weeks later...

i'm really confused and I feel like i'm making this more complicated than it should be....I'm trying to figure out how to do the second part.

"What type of function models the behaviour of the graph? Explain why you chose this function. Create an equation (a model) that fits the graph."

I know i want to use a cubic equation in the form of y=ax^3+bx^2+cx+d. i dont know how to solve for variables a,b,c,d and to be honest i dont understand how to explain why i chose to use a cubic apart from that the shape looks like it could fit.

could anyone please help me on how to manually find the equation for the model of a cubic?

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It's polynomial of 3rd degree or higher. Should you choose this option, I've posted the instructions on how to obtain polynomial of any degree (up to maximum number of points in your set of data, to be precise) here. You will find data for median BMI of females here. Another option is to mess around with the sine or cosine function. I can also assist you with this one if you like, but I'd go for polynomials if I were you. ;)
your postings don't work! ;) help...
Hey all :) I've been trying to find some past IB SL Type II math papers and the ones I've found have been ridiculously long.How long (number of pages) was your BMI task?
Oh where did you find them???? I've been looking everywhere for an example!
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  • 2 weeks later...

Our Maths teacher gave us a program to download (Autograph 3.0) which you can get a 30 day free trial of.

And from that..

Plug in all the data, then just try find an equation to match it using Trial and Error.

...Okay, not exactly an 100% Mathematical approach; but we looked a sample piece which used Trial and Error and they got 19/20.

So, might as well mess around with it.

P.S. You can just right click on the data points and add a line of best fit to any power; but you don't get good marks for it.

Hope this helped;

I'm struggling though this as we speak =]

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lol yeh i have no idea what a gaussian function is.. and since its due on friday I think i'll stick with the cubic for this one :)

and mm i understand that it repeats, which BMI clearl doesnt..but its also not meant to go negative, so im considering it within a specified domain

...

what would the difference be then?

BMI doesnt repeat but it does have many local mases and mins...you could rotate a cubic or quartic or even a cinctic so that it meets all of the generic maxes and mins which would represent the normal female cycles in cellulite gain just use tan2theta=B/A-C for radian measure of rotation and it should work out fine

thats what I'm doing but this is only my second IA, but I got a 19 on my first one

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Hey all :)

I've been trying to find some past IB SL Type II math papers and the ones I've found have been ridiculously long.

How long (number of pages) was your BMI task?

Roughly 20 pages cause my graphs were huge, but my teacher says that less than 10 pages can get you a very high mark as well.

My last one was 39 pages long single spaced and around 80 pages double spaced but thats because I went way in depth. There were people with 20 page long papers who got really good scores too tho so it needent be quite that long

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  • 2 months later...

Do you want to explain the assignment first? We're not mind readers...

The Body mass index maths SL portfolio, we model a function that imitates the BMI graph, and then discuss limitations to the model >< As far as i know there is only one BMI portfolio >.>

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