hero123321 Posted February 7, 2009 Report Share Posted February 7, 2009 hi guyz, i am doing the BMI IA, and i am little but confused of wat to use and wat not to use, okay so the third question in the portfolio asks to draw the model that i have already deduced in question 2 (i have used a sine function to model the data), the 4th question asks to find another function that models the data, does that mean that i have to use technology to find a better sine equation, or just use another function like polynomial or something. i would really appreciate ur helpthanks in advance 1 Reply Link to post Share on other sites More sharing options...
supbhang Posted February 7, 2009 Report Share Posted February 7, 2009 Well, what I did is- I wanted to draw a cubic equation. I took 4 values and I got 4 variables and 4 equations. Thus, I was able to get the equation for my model.- In question 4, I used the "Cubic Regression" on my calculator to draw an even more accurate graphWell, that's what I "interpreted" out of these questions. I hope that helped Reply Link to post Share on other sites More sharing options...
hero123321 Posted February 7, 2009 Report Share Posted February 7, 2009 Well, what I did is- I wanted to draw a cubic equation. I took 4 values and I got 4 variables and 4 equations. Thus, I was able to get the equation for my model.- In question 4, I used the "Cubic Regression" on my calculator to draw an even more accurate graphWell, that's what I "interpreted" out of these questions. I hope that helped no need for all the explanation lol, thanks anyways, so ur saying that i should do sine regression on my calculator for the 4th question and not make a whole new function Reply Link to post Share on other sites More sharing options...
supbhang Posted February 8, 2009 Report Share Posted February 8, 2009 (edited) You're welcome Yeah, I think that'd be alright!!EDIT: Have you found other BMI data for the last question?? Edited February 8, 2009 by supbhang Reply Link to post Share on other sites More sharing options...
blair xoxo Posted February 8, 2009 Report Share Posted February 8, 2009 hye guys.. anyway i dont find the BMI data from other country..any clue? Reply Link to post Share on other sites More sharing options...
blair xoxo Posted February 11, 2009 Report Share Posted February 11, 2009 im really stuck with the whole internal assesment hahacan someone maybe help me ? i still dont get wat a parameter is and i dont get which functions to use and i dont get how to mention common differences in the graphs lolll.yea i also not sure with the parameters..any idea?cos i need to send my ia this week Reply Link to post Share on other sites More sharing options...
supbhang Posted February 11, 2009 Report Share Posted February 11, 2009 Yeah thanks a lot for the data. I must've skipped those posts with the data Reply Link to post Share on other sites More sharing options...
caro Posted February 12, 2009 Report Share Posted February 12, 2009 hey I really hate this project. working on it right now. However I have found a table Conde, Wolney. "Body Mass Index distribution for a Brazilian referenced population." Table 1. 29 Apr. 2006. 12 Feb. 2009.But you need to convert it. just in case it is a long way... hate math Reply Link to post Share on other sites More sharing options...
filmjolk Posted February 15, 2009 Report Share Posted February 15, 2009 (edited) Parameters = the units etc representing the x and y axis. In this case the BMI and the age are parameters, and they need to be on the graph.A question that I wanna raise is if you need to make a curve on the first graph, it only tells you to plot the data points on a graph. Define all variables??? such as a, b and c? or in terms of defining the age/bmi with domain. Ex: age cannot be less than 0Edit: remember that x-axis is controlled. Edited February 15, 2009 by filmjolk Reply Link to post Share on other sites More sharing options...
blair xoxo Posted February 15, 2009 Report Share Posted February 15, 2009 thanks filmjolk..anyway what i did is I define the variables as age and bmi ---using domain and range,where domain is x and range is y Reply Link to post Share on other sites More sharing options...
razord8 Posted February 18, 2009 Report Share Posted February 18, 2009 Hi guys,First of all I would like to say a warm Hello to all of you as I am new on these forums.I am a Year 12 IB student and I have been given this assessment to do.I'm sure a lot of you have done this assessment and I'm hoping you guys can help me out.I'm pretty much stuck on what to do for each task. I have a general idea, but am clueless on what to do precisely to answer each question.If anyone could be so kind to give me a quick breakdown on what to do, I would appreciate it so much. Or even just a few tips or instructions for a single task would also be great.Thanks so much in advance! Reply Link to post Share on other sites More sharing options...
cheebs Posted February 19, 2009 Report Share Posted February 19, 2009 well first thing i did was draw the curve of the BMI data in excel so I could see what it looks likefrom that I found a function which would model the data (when you see what the curve looks like you should be able to figure out which function you need)for the 2nd formula just play with the curve in excel by using the regression tool Reply Link to post Share on other sites More sharing options...
filmjolk Posted February 20, 2009 Report Share Posted February 20, 2009 and I would strongly recommend you to get lots of software. you will have to find lots of roots and other stuff in this assignment.software ex:autographgraphmaticamicrosoft mathmaple 12there are many more, but I managed with theese and microsoft office. Reply Link to post Share on other sites More sharing options...
Chelleee Posted February 21, 2009 Report Share Posted February 21, 2009 ahh i did this last year! i first found chose a country (america - easiest to get data for) and then i found out the average BMI and got a graph to show the range of the population (anorexic to obese)and then i put up the graph given and began talking about how i came up with the final equationand then i babbled about accuracy of the models and then finished off with limitations and errors.hope that helps somehow. Reply Link to post Share on other sites More sharing options...
Viki Posted February 24, 2009 Report Share Posted February 24, 2009 hey so ive done most of this portfolio.. but im having trouble explaining WHY i picked the graphI chose a cubic, but why is this any better than a sine/cos/etc?so confused.. any help would be appreciated! Reply Link to post Share on other sites More sharing options...
deissi Posted February 24, 2009 Report Share Posted February 24, 2009 hey so ive done most of this portfolio.. but im having trouble explaining WHY i picked the graphI chose a cubic, but why is this any better than a sine/cos/etc?so confused.. any help would be appreciated!What happens to a sine function after a certain period? Consider the standard sine function and you should understand. Reply Link to post Share on other sites More sharing options...
spartan12103 Posted February 25, 2009 Report Share Posted February 25, 2009 I agree that people do not get fat in "waves", but you have to take into consideration that the quatric and cubic functions are only accurate for a short period of time. I would use a Gaussian fuction, but we have not learned that in class yet and it would be difficult to explain on my own. Also, my teacher would be suspicious because we haven't even touched on that topic. So I'm stuck with a sinusoidal equation. *sigh* This question is a lot more complicated than past ones I've seen. We did practice problems in class, and both the tide problem and crows dropping nuts problem are a lot more straightforward. Reply Link to post Share on other sites More sharing options...
spartan12103 Posted February 25, 2009 Report Share Posted February 25, 2009 ahh i did this last year! i first found chose a country (america - easiest to get data for) and then i found out the average BMI and got a graph to show the range of the population (anorexic to obese)and then i put up the graph given and began talking about how i came up with the final equationand then i babbled about accuracy of the models and then finished off with limitations and errors.hope that helps somehow.I'm pretty sure you're supposed to choose BMI data for females from another country not from the US. Reply Link to post Share on other sites More sharing options...
Viki Posted February 25, 2009 Report Share Posted February 25, 2009 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? Reply Link to post Share on other sites More sharing options...
filmjolk Posted February 26, 2009 Report Share Posted February 26, 2009 (edited) Look at the gaussian function as a bell curve, all you have to do is flip it horizontaly, shift it a little bit, and then add a new y-intercept. I would suggest to the guys who do use a gausian to invest some time in an inverse gausian, unless you feel it is way outside of the syllabus, in which case you could briefly mention that an inverse would perhaps have an even better fit due to it's exponential nature.But do investigate how bell curves will fit the data, they don't go negative unless you want them to Edited February 26, 2009 by filmjolk Reply Link to post Share on other sites More sharing options...
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