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Type II -- Population Trends in China


Karl H T

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GOD. I'm done:D And it's due tomorrow :)

So since I know first hand how hell-like it was, I will be more than happy to help anyone who needs some tips. I must highlight that I do not know whether I did it ok, but I think any help is still better than no help at all?:o

Can you Please help me with what K L and M mean?

thank you

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I am struggling on finding a software that will graph the Logistic function. Everytime i try to graph it, it always ends up giving me a reciprocal function no matter where i graph it. Can anybody help me with this? I have tried using Graphmatica and Geogebra and I am not getting anything from them.

As well, I do not know how i can create an equation good enough using matrices. All i can do is use the number of values that i am making the polynomial function and therefore it will not incorporate all of the values and the equation i get is WAY off compared to what excel is giving me.

Can you guys please help me as soon as possible. I have been working on this for a bit over a week and i am really confused as it is due soon. Thanks in advance.

i used autograph...worked best for me and i figured out how to work it very easily

i'm doing fine with the maths part.

i don't understand what they mean by "discuss the implications of each of these models in terms of population grown in china in the future"...are they just asking us to extrapolate?

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i don't understand what they mean by "discuss the implications of each of these models in terms of population grown in china in the future"...are they just asking us to extrapolate?

Hey I am not doing this task and some parts are confusing me so I can't help much, but I think they might want you to extrapolate the graph or substitute something to the equation they gave you. I don't know though since I didn't put in much effort to get the answer :) so I can't help with this IA..


Did you guys all use excel to make your graphs? Is there a way to have it work like the TI calculator graphing interface or do you need to find another program for that?

Hey I am not doing this task but I just want to help people around, but again unfortunately I don't really get the task so I wouldn't say much as I might not lead you to the right track.

I tried plotting the graph using Autograph but the best fit line does not even pass through any of the data point and I think it was not the desired curve anyway. I tried plotting using Excel and got the expected graph. Is it 6th polynomial? If yes then I'd suggest you to just stick with Excel.

I don't think I tried my TI but I thought TI can't give you the equation of the graph? Or maybe I just do not know. Excel is a form of technology usage too anyway so you should be fine.

But again I am not doing this task so idk if Excel can help you throughout the portfolio.

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is this for Population Trends in China?

I think Parameters can be any numbers.

I do not know if you learn this in SL, but let's say you have 3 expressions in which there are 3 variables: x, y and z.

Example:

2x+2y+z=1

3x+12y+3z=6

x+4y+z=2

Solving the above equation by doing RREF, it wil turn out that z is a parameter, z=t given that t is a real number

6y+z=3, y=(3-t)/6

3x+z=0, x=-t/3

That means, t can be anything. can be -8, 0, 1.2, 23, 94, etc... and thus the solution of the system is a straight line

I hope I explained it correctly and you get what I mean

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I don't even know where to start for this portfolio... I'm so lost.

Specify your question, please? :panic:

You should start with plotting a graph. I would suggest putting a proper table btw but idk if that's necessary. IMO it is. Define all relevant variables and parameters. Then plot the graph. If you see a trend, talk about it. (does it increase or decrease..? how does the graph look like? what do you think the type of function is?)

Then just answer the following questions. Any doubt or question just post here, I'll try to help you XD

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This should help some: http://cerebro.xu.edu/math/math120/01f/logistic.pdf [the bold stuff haha]

Plugging numbers in usually helps as you keep the other two variables constant. K is the easiest. Making t infinitely large will show you what K is, which is explained on that site.

YOU ARE AWESOME. This is an extremely helpful pdf on the logistic function, but unfortunately I wasn't able to pinpoint the source of this pdf... where did you get this pdf file? I'm afraid I would have to cite such a valuable source haha :P.

The source of this data/work sheet is much appreciated.

Thank You!

Edited by Jeff Chen
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hello, how do you get the parameters of K, L , M. I looked at the pdf posted on the first page but I am still confused o how to get the Parameters.. can someone please help me? :D

p.s What is regression??

Hey. If you have a GDC like TI-83 or TI-84 this should be easy. Go to STATS then then click on edit and enter all the data that was given. The years are too large and makes it harder to graph so you can input 0,5,10,15,20,25,30,35,40,45. These are the exact intervals as the years so the accuracy is fine. After you enter both the year and population value quit and then go back to STATS. Go across to CALC then scroll down all the way to logistic...which is B I believe then press enter then put L1 and L2. Then waalaa you have your parameters. :blink:

well, isn't it depending on which function you use? because i get like y,a,b,c...so what are these letters for?

thanks

The y, a, b, c represent the different letters for the researcher's model. If you look at an original logistic function that should be able to help you figure out which letter from the calculator matches the letter from the model. For example, C would represent K. Hope this helped you. :)

finding the actual estimates of K, L and M isnt that hard..

but how do you interpret them?

am i supposed to find out the factors affecting chinas population to change as in which constant would be the birth rate death rate etc.

or what the logistic link tells you..

about that when x increases -bx decreases and e^-bx decreases wherefore 1+Ae^-bx is always larger than 1 approaching 1 as x gets larger???

http://cerebro.xu.edu/math/math120/01f/logistic.pdf

please help :(((

Edited by Stay_Gold8
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i got the same ia too on monday! and its due in two weeks! I used autograph to do my previous practice ia's for math but my trial has run out! AND IM IN DESPERATE NEED for a suggestion of an equivalent to autograph or maybe even the serial number. Excel's alright for me but im a mac user so excel is quite horrid. so could someone recommend a software i could use? ID REALLY APPRECIATE IT!(:

maybe you can use Omnigraph?

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I need some serious assistance with finding a program that will not only plot all ten data points but also will graph the function that the researcher gives. I have tried everything that comes up in the google search for online graphs. Help would be greatly appreciated. :]

If you have TI-Nspire, use it. I use TI-Nspire Student Software. If you need info on how to use it, I'll be sure to help.

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What does it mean when it says: Define all relevant variables and parameters clearly. ?

Please try and put it simply, I'm not very good at this sorta thing...

Yeah you have 2 variables, right? Year and Population, so I guess you can use the letters t and P respectively.. Just describe that t is year and P is population in millions and also state whether t and P are integers or real numbers or whatever..using mathematical notations :)


hi, i was just wondering...

i am using different programs to graph, write equations, and such

but how would IB know that i used these programs?

do i include the names of programs i used in my portfolio?

thanks in advance.

I do not know if your teacher told you to do this but my teacher actually asked us to write an introduction (one paragraph will do) to introduce the problem, explain what the investigation is all about, aim of investigation and also the softwares that you use :)

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when they ask "use technology to estimate..." do we explain what we did on the programs to get the values for K, L, & M ? or do we just state that we used these program and the values were... ?

You should perhaps describe briefly what you did with that program to get the values of K, L and M. Like maybe you plot the graph and use that program to find the equation in [insert type of function (e.g. logarithmic, exponential, quadratic, etc.)] form, then those are the values of K, L and M. And put a screenshot to show that it's what that program told you if you can :)

Detailed procedure of the steps is not necessary, though, like click this, insert this, click OK, and stuffs like that.

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