IA Type II -- Population Trends in China

[Alex Koo]

Hmmm this is very hard to explain.. I will try to write out a clearer explanation on how the rref works and scan and upload it later because TBH what I wrote that time was too confusing yeah. You may want to try to google it first: how to solve 3x3 matrices using rref. TI-84 should be able to do that too.

I am not sure about the IMF part since I haven't actually tried it out. I guess what you need to do now is to plot the IMF data together with your model and make some changes to your model so that it fits the IMF data. I am not so sure on how though, I will try that later!

Alright will do! Thanks a bunch man (: Really helping me out. Wouldn't it be solving 4x4 matrices though? Or 3x3.

[Youcandoit]

I'm doing the same investigation and i need some help T^T

I used 6th polynomial function for my model equation but few points came out to be really off from the original data

same as the 3rd and 7th function..

all points i used to calculate the cosnants came out to be exactly the same but when i used the equations to solve the other points,

the answer came out really far off from the original data..

did i do something wrong?

what is the problem?

or what other type of equation can i use to get better graph that fits the original data? T^T

[dessskris]

Hey youcandoit and alex, I finally wrote it already! Here it is.

How to Model a Quartic Function

I think you should be able to model other polynomial functions from there because the idea is about the same.

FYI if you don't want to use rref, you can actually solve for a, b, c and d using elimination and substitution.

Also, you can use inverse to solve the matrices instead of transforming it into an augmented matrix and doing rref. Be careful, just find the inverse using calculator, don't do it yourself because finding the inverse of 3x3 or 4x4 matrix is not as easy as finding the inverse of 2x2 matrix.

I will try to figure out the IMF modification thing..and youcandoit if you still have problems please ask again, specify your question, I will try to help!

Edited May 4, 2011 by dessskris

[gsaunders]

If any one needs help with this task, I finished it last term, so just ask

Got 19/20 points on it, so thats AWESOME

I could use some help as well, what function did u use, i was thinking of using wither an exponential (so that the graph never goes below zero) or the cubic (cause if fits great with the points), but i have no friken idea how to find a,b,c,d (in a ax^3 + bx^2 + cx + d) or a,b (for ae^bx) analitically... any idea??

Try Matrices, that's the easiest way to do it. How do you interpret K, L and M ?

What did you do with the matricies? How did they help?

[dessskris]

Try Matrices, that's the easiest way to do it.

What did you do with the matricies? How did they help?

Read my post just above your post! The one with the big picture

[hey23]

What is the interpretation of K, L and M for the population trends in china assessment?

[megan_doyle]

Hello to everybody!

I am nearly finished with this one, only wondering whether it is better to include graphs that show grids or ones that do not. Does that makes any difference whatsoever?

What program is this? I have Graphical Analysis 3.4 but it doesn't have the option for logistic functions so I'm looking for a new one to download.

[dessskris]

What is the interpretation of K, L and M for the population trends in china assessment?

They are parameters, which means they might represent something in this population context. Try to research about factors that determine population, or maybe ask a Geography teacher

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What program is this? I have Graphical Analysis 3.4 but it doesn't have the option for logistic functions so I'm looking for a new one to download.

From the red data point dots and red line, I would guess that it might be TI-Nspire Student Software. But then the font is different and the axes look a bit different so it might be another software. Anyhow, I suggest purchasing TI-Nspire Student Software because it can model a logistic function or I think TI-84 can do it too..not sure, though. Try using your TI if you have one.

[hey23]

What is everybody using matrices for? the K, L and M equation or for the model function that fits the data points on the graph?

[paperpheasant]

Hmmm this is very hard to explain.. I will try to write out a clearer explanation on how the rref works and scan and upload it later because TBH what I wrote that time was too confusing yeah. You may want to try to google it first: how to solve 3x3 matrices using rref. TI-84 should be able to do that too.

I am not sure about the IMF part since I haven't actually tried it out. I guess what you need to do now is to plot the IMF data together with your model and make some changes to your model so that it fits the IMF data. I am not so sure on how though, I will try that later!

I have figured out in the part saying 'modify' to type all of the data given in both tables and from this data calculate with logistic regression the parametres K,L,M and substituted it to the researchers function, do you think it would be alright then as for modify.?

[dessskris]

What is everybody using matrices for? the K, L and M equation or for the model function that fits the data points on the graph?

I am not doing this task but I reckon matrices can be used to model a function. The one you are asked to model first.

Then the K, L and M equation (researcher's model) can be found using your graphing software without performing any calculation I would say.

---

I have figured out in the part saying 'modify' to type all of the data given in both tables and from this data calculate with logistic regression the parametres K,L,M and substituted it to the researchers function, do you think it would be alright then as for modify.?

Sorry I don't quite understand that did you mean you plotted the data from both tables and then use your graphing software to find the logistic regression? Hmmm sorry I do not know much about this question actually but I think they want you to modify analytically not sure though.. I think it might be possible too but not sure. Ask your teacher whether you should modify your model function analytically or you can use technology for that.

[chuck1norris1]

I'm doing the same investigation and i need some help T^T

I used 6th polynomial function for my model equation but few points came out to be really off from the original data

same as the 3rd and 7th function..

all points i used to calculate the cosnants came out to be exactly the same but when i used the equations to solve the other points,

the answer came out really far off from the original data..

did i do something wrong?

what is the problem?

or what other type of equation can i use to get better graph that fits the original data? T^T

I am having the same problem as Youcandoit, some of my points are screwed up when I used the 6th polynomial function for my model equation. I tried using the "How to Model a Quartic Function" post but that still didn't work. Help, mine is due in one day!!!

[helenpark]

I cannot figure out how to plot a logistic function either... tried already Loggerpro and Autograph =(

Autograph cant plot logistic function.

use your GDC!

[Youcandoit]

I'm on my last question..modifying the model that applies to all given data from 1950 to 2008

T^T any hint on what i should be doing?

By the way, Desy thank you so much for your "how to model quartic function"

it helped me soo much!

[dessskris]

I am having the same problem as Youcandoit, some of my points are screwed up when I used the 6th polynomial function for my model equation. I tried using the "How to Model a Quartic Function" post but that still didn't work. Help, mine is due in one day!!!

You should have started doing this portfolio like at least 3 days ago so you have more time to ask here if you are stuck!!

I think it depends on your method. I guess you might have made a calculation mistake or you did it wrongly..

Hints:

• Convert the time to small constants (0<=t<10)
  
• Read my How to Model a Quartic Function picture. If you want to model a 6th polynomial function, your general function would be P=ax⁶+bx⁵+cx⁴+dx³+ex²+fx+g where a,b,c,d,e,f and g are constants, real numbers. If you have a coordinate (0, y) then you can get the value of g thus you only need to solve for a,b,c,d,e and f. So you take 6 more sets of values of x and y and then get 6x7 augmented matrix (let it be A) and then put rref(A) in your GDC and the numbers on the 7th column are the values ofa,b,c,d,e and f

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@Youcandoit you are welcome! Glad to know I have helped! I'd like to apologise though because I can't help much on that part.. I haven't figured out how it is supposed to be done and whether they expect you to do it analytically or can use technology. I would try looking at past Type II IA's that got good marks and see if they had done anything similar so I could guess what to do in this part.. But I guess re-modelling the function will do..? Not sure, though, I don't know. Sorry!

[You Kyum Kim]

Yes, go with grids It looks better like this Btw I used the same program and it was very helpful. If you have any problems I can help, since I finnished that portfolio already. I must say that the use of technology was pretty hard, so if you need anything I'm willing to help Good luck

Hi, i am also doing this portfolio and i am having a struggle in using which software to do the graphs. if you can, please suggest one for me. Thank you@!!

[dessskris]

Hi, i am also doing this portfolio and i am having a struggle in using which software to do the graphs. if you can, please suggest one for me. Thank you@!!

Read this thread, just jump straight to the Graphing Software part. I personally recommend TI-Nspire Student Software if you have one. It's really helpful in finding the logistic function.

[IBinNeedofSomeHelp]

Hi!

I was given my IA 9 days ago and have been unwell so haven't actually had a chance to really do a lot of work on it. This, coupled with two crappy teachers, has left me to struggle my way through it tonight; for tomorrow morning. I understand that no-one can show me the answers or anything like that but I honestly have NO idea what I am doing. Not at all.

I understand relevant variables are reasons why the x and y axis won't get past a certain stage, death rates etc and all of that information. But I cannot do logistics and have been told that Geogebra is a good way in which to start.

If anyone could help me I would be extremely grateful!

xo

[dessskris]

Hi!

I was given my IA 9 days ago and have been unwell so haven't actually had a chance to really do a lot of work on it. This, coupled with two crappy teachers, has left me to struggle my way through it tonight; for tomorrow morning. I understand that no-one can show me the answers or anything like that but I honestly have NO idea what I am doing. Not at all.

I understand relevant variables are reasons why the x and y axis won't get past a certain stage, death rates etc and all of that information. But I cannot do logistics and have been told that Geogebra is a good way in which to start.

If anyone could help me I would be extremely grateful!

xo

HAH you should have started like at least 3-5 days ago read this whole thread and if you still have any doubt/questions just ask!

I am sorry but you didn't really specify your question so idk how to help you. What do you want to know? Which part do you not understand? Have you modelled your function? Start with focusing on your portfolio and don't think about anything else!! Good luck!

[IBinNeedofSomeHelp]

Hi!

I was given my IA 9 days ago and have been unwell so haven't actually had a chance to really do a lot of work on it. This, coupled with two crappy teachers, has left me to struggle my way through it tonight; for tomorrow morning. I understand that no-one can show me the answers or anything like that but I honestly have NO idea what I am doing. Not at all.

I understand relevant variables are reasons why the x and y axis won't get past a certain stage, death rates etc and all of that information. But I cannot do logistics and have been told that Geogebra is a good way in which to start.

If anyone could help me I would be extremely grateful!

xo

HAH you should have started like at least 3-5 days ago read this whole thread and if you still have any doubt/questions just ask!

I am sorry but you didn't really specify your question so idk how to help you. What do you want to know? Which part do you not understand? Have you modelled your function? Start with focusing on your portfolio and don't think about anything else!! Good luck!

Thank you for your help! First time I've looked at this site and I'm kind of excited (getting a reply made me happy).

I know I was really vague on what I can't do but to be honest I've had NO help whatsoever as my teachers insist that they aren't allowed to give any help without marking us down. And the teachers themselves have hardly taught me anything over the past year and a half. I'm having problems creating the model functions and knowing how to use sliders etc on Geogebra. It's all a bit confusing and to be honest I'm not the only person in my class who cannot do it. The logistic I don't really understand at all and am not sure how I'm supposed to plot it; or where?

I'm not sure how much help you can give me, but I think I've read through pretty much EVERY thing about this on this website and still am having a bit of difficulty! It appears that everyone other than myself knows how to do this piece of coursework, or at least seems to be on a higher level than myself.

Thank you for bothering to reply! xo