IA Type II -- Population Trends in China

[CkyBlue]

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?

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.

When I followed these instructions, it worked for me, however I even tried plotting it putting the values 1950-1955 instead of 0-45, and I get a different, must steepher graph. In my calculator, only the value for a changes. How come the two graphs are different? If the intervals are the same, shouldn't the graph go through the points? What explains the shape of this graph?

Perhaps your function by regression did not take into account the points from the rest/or all of the plotted data. The two graphs are different because the plots of data are different. Regression takes into account all the plotted points, so the graph for 0-45 is different from 0-55 or 50-55. Also, regression isn't perfect. I believe it is only to model the trend of the points while making them as close as the actual points as possible. Try modelling a quadratic function with a linear. It won't work. And it's not perfect. The shape of the graph, well, I'm pretty sure you should be familiar with what all the parameters do.

[Olga Gonzalez]

What exactly do I have to talk about when they ask for the implications of the two models? Thank you!

[Olga Gonzalez]

how do you find K, L and M...?

is it using regression or matrices?

You could use your calculator. Does it have a Statistics option?

[Olga Gonzalez]

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??

Hey, so how did you find a,b,c and d? It would be really helpful, because I am really confused..

Thanks!

You can substitute coordinates in the cubic model and then use a matrix, and its inverse, to get the values

[dessskris]

first off you don't need to answer very old questions because:

1. it's very likely that they have finished this task anyway.

2. they might have figured out the answer to their own questions.

to your question, for the implication, it's like: if the graph keeps increasing, it implies that the population will keep increasing. if the graph will reach its maximum population at year X, it implies that in that year something will happen and the rate of death >> the rate of birth. if there is an asymptote or whatever you can observe from the graph, just explain it in terms of the population.

[Sid_thesloth_FromIceAge]

Im new to excel and I am having trouble plotting my model. I have analytically developed my model, but I dont know how to a graph it and the given data points at the same time in excel/word . Im using the 2007 version

[dessskris]

Im new to excel and I am having trouble plotting my model. I have analytically developed my model, but I dont know how to a graph it and the given data points at the same time in excel/word . Im using the 2007 version

don't use excel. it's not going to be any help in this portfolio, especially with the researcher's model. try to use your GDC.

[Sid_thesloth_FromIceAge]

Im new to excel and I am having trouble plotting my model. I have analytically developed my model, but I dont know how to a graph it and the given data points at the same time in excel/word . Im using the 2007 version

don't use excel. it's not going to be any help in this portfolio, especially with the researcher's model. try to use your GDC.

How would i go about including graphs off my GDC and are there any other recommended programs for this?

Im new to excel and I am having trouble plotting my model. I have analytically developed my model, but I dont know how to a graph it and the given data points at the same time in excel/word . Im using the 2007 version

don't use excel. it's not going to be any help in this portfolio, especially with the researcher's model. try to use your GDC.

[dessskris]

How would i go about including graphs off my GDC and are there any other recommended programs for this?

connect it to your laptop, install the software, take screenshots. of course this depends on what GDC you have, but if you use TI that's how it works.

so far, no there is no substitute for TI. it's the only software that can generate a logistic function (the researcher's model) so you better use it.

I know other software that can be used for parts other than the researcher's model, but it's best to stick with using one software in the whole portfolio, so use your GDC.

[Sid_thesloth_FromIceAge]

How would i go about including graphs off my GDC and are there any other recommended programs for this?

connect it to your laptop, install the software, take screenshots. of course this depends on what GDC you have, but if you use TI that's how it works.

so far, no there is no substitute for TI. it's the only software that can generate a logistic function (the researcher's model) so you better use it.

I know other software that can be used for parts other than the researcher's model, but it's best to stick with using one software in the whole portfolio, so use your GDC.

Thanks for the help I will see if I can find the cable to connect it to my laptop. Do you know if I can download the Ti software somewhere else if I dont have the cable, like the pirate bay or something?

[dessskris]

Thanks for the help I will see if I can find the cable to connect it to my laptop. Do you know if I can download the Ti software somewhere else if I dont have the cable, like the pirate bay or something?

wait which TI do you use?

TI Nspire has a computer software that can be used without having to connect the calculator to it, but I think you can't get the full version because it requires you to enter the code printed somewhere in the calculator package (can be used only one, will be verified online) so yeahhhh idk though.

for other TI versions, idk but maybe you'll need to connect the handheld to your compie.

but if you still have the package, inside there's a CD from which you can install the computer software.

[dessskris]

so is this convo. about math or china?

it's a Maths IA, so this convo is mainly about maths.

why?

[Sid_thesloth_FromIceAge]

What time of function should I develop? Ive been told exponential, cubic and even linear. Anyone who has completed this idea/has a good idea of what it is please help

[Iwuvtb2]

What time of function should I develop? Ive been told exponential, cubic and even linear. Anyone who has completed this idea/has a good idea of what it is please help

I found cubic to be the best. Im doing mine right now. Due in 2 days

[dessskris]

What time of function should I develop? Ive been told exponential, cubic and even linear. Anyone who has completed this idea/has a good idea of what it is please help

I found cubic to be the best. Im doing mine right now. Due in 2 days

woahhh good luck!!!

my best model was 6th poly

[Iwuvtb2]

What time of function should I develop? Ive been told exponential, cubic and even linear. Anyone who has completed this idea/has a good idea of what it is please help

I found cubic to be the best. Im doing mine right now. Due in 2 days

woahhh good luck!!!

my best model was 6th poly

Yea i was kind of wanting the 6th poly model to fit the best seeing how it took the longest to figure out. Im actually almost done now. I just have to do the very last part and then i skipped one part in the beginning. I cant think of a good way to explain why I chose a cubic polynomial equation over the other ones.

[Guest]

Even i found Cubic to be the best. Logger Pro seemed to match that the best.

Anyhow I think we can justify the use of Cubic by saying something like there were technological or time constraints. Because i know for a fact that I could have gone onto 6th degree but Logger Pro wasn't being able to calculate it correctly.

Oh and just an afterthought, after much analysis I found that the 'Gaussian function' (y=A*exp(-(x-B)^2/(C^2))+D) is the best fit and it makes the best prediction.

[hlffthjtsttrs]

When they ask to explain my choices of what types of functions can model the behaviour of the graph, do I have to explain them with the use of technology and other graphs or can I just state that for example it is increasing so maybe linear function can model it or exponential beacause it's upward-sloping and so on?

And can I choose which one I will develop analytically basing only on my opinion (just stating that to me it appears to be the best so I will describe only this one)

I'm really lost...

Edited November 8, 2011 by hlffthjtsttrs

[dessskris]

at that stage, include graphs only if necessary. you are rather expected to describe the characteristics of such function which make you think it will suit your data. don't base it merely on your opinion, you need to give mathematical reasoning.

[hlffthjtsttrs]

Thanks, and when they ask to discuss implications of each of these models do they refer only to researcher's model and the original data or to my model also?