IA Type II -- Gold Medal Heights

[Iradesca]

I know I'm going to sound like a complete lazy idiot when I say this, but would someone please help me analytically create a linear regression equation? I can't seem to get these IAs. My mind goes completely blank when I do one. Thank you in advance!!!!!

linear? you sure? linear regression is y=mx+c which doesn't fit the data.

sorry we CANNOT help you create any function, we can only guide you through it.

PS. you might want to consider dropping down to maths studies if you don't even want to put in my effort in your IA.

I was only taught how to do the linear regression calculations in my calculator. My teacher has not taught me any of the other equations mentioned in this forum (either that, or I still don't know the terminology). I was not asking for someone to give me the equation. I was only asking for a little help and guidance. I have put effort into this IA. Like I said, my mind seems to go blank when I try to do one. I know this is no excuse, but it's the truth. I am not dropping down. I know I can do it. I just need a little help.

Edited January 3, 2012 by Iradesca

[Indre]

I have a question about how to use GeoGebra.

Well, when I used it to find technologically the function that models the data, it showed me the equation starting: 0x^9+0x^8+0.7x^7... The problem is, when I substituted this equation (omitting 0x^9 and 0x^8) into another programme "Graph", I got a completely different function than GeoGebra gave. I supposed that those constants that GeoGebra showed to be zeros were not really zeros.

Could anyone help me find out those constants with GeoGebra?

Thanks a lot!!

[~feather~]

kill your teacher for telling you to do an IA with no background knowledge or such.

which task is this anyway?

The gold medal heights task 2

umm is there anything you want to ask? for how to find a model, click here --> http://www.ibsurviva...post__p__137034

I know it's from a different task, but all the Maths SL type 2 tasks are basically asking for the exact same thing, just that each task has different data to analyse.

any question you can ask here.

Hi, Desy, thanks a lot for your help. I read all the posts here several times and they really helped me. However, I still have some questions.

I just analytically created a polynomial function to 5th degree, I think it fits the data quite well since it shows the main trend (but it doesn't fit all the data points, just few of them. Is that okay?) Then the task asks to refine the model if necessary. How should i refine it? Is it possible to somehow change it a bit that it would fit more points of the original graph or is it okay to leave my function as it is now?

What's more, can I just use the "best fit" curve proposed by "Autograph" for the technologically created model? Even if it doesn't fit all the data points? I think that polynomial function to 8th degree is the best choice here, so can I use its equation, written by "Autograph" for this model?

P.S. the variables in my graph are still converted to lower values, is it ok? Or do they need to be converted back to the high ones (e.g. year like 1932, 1936, etc.)? If I convert them back, any of "Best fit" curves doesn't seem to fit the graph.

Edited January 8, 2012 by ~feather~

[thuytrang]

do you know what it means by "Discuss any possible constraints of the task"? Does it mean what problems we might encounter while trying to create the line of best fit?

[thuytrang]

Hi,

We just got this IA today, and our teacher told us that parameters were unknowns that we would find in our investigation. For example, in a quadratic equation,

y = a(x-h)+ k

the variables are x and y

but the parameters are a, h, and k

Hopefully that helps?

So when it says state your parameters, you would simply say: In the function that I chose, the parameters of the function would be a, h and k.

Is that correct?

[rushmie]

How do I start off for creating an equation to model the data analytically? is there a certain equation I should use?

you need to first choose what kind of function you want to model. then state its general form and then solve for the constants by plugging in values of x and y

I dont understand how you can solve for both constants at the same time?? for example with y=ax+b, there are two constants even after plugging in for x and y

[Guest rod4eva]

I'm kinda lost on this .. i'm right at the beginning any help on how to start ? I have autograph and logger pro to help plot the graph.. do i need to fill in for the years that are missing ? do i need to predict ?

thnks in advance !

[JennIB12]

well if linear looks best on your calculator then go for it

I think it depends on what software you use to generate the regressions. mine gives quartic as the best regression. but if you get a linear one then okay.....

there is no best function IMO. in my opinion that is. if there must be a best function it'd be tangent but the first two data points do not fit...

How did you graph the quartic function? I'm working on this paper now and I can't figure out how to graph it on the computer! Also, what kind of limitations would it have?

[Gonzalo]

Is anyone else finding it exceptionally tedious to find a proper program to build all these models on?

I have practically finished the IA on my GDC, I have it all written out but I cannot find a program that is simply enough for me to graph my information correctly and such...

I have tried GeoGebra, it just led to confusion because I am relatively new to it and like usual, excel makes NO sense.

Help?

[drummermcjohn]

ATTENTION: If you have access to a MAC, use it!

All OSX Mac's should have a program natively installed called "Grapher."

It is simply the bomb. It is intuitive, and then you can just take screenshots of the graphs you want and then drag the pictures into your word document. It is the best graphing software out there, imo.

[FRdupuis]

Hey, I just got my mark for this IA, and I got a 12, so I'm really really sad. I didn't get my actual paper to see what I did wrong, but I'm really depressed now.

So my question is: Is it still possible for me to get a 7 in Math?

My current course mark is a 6, and I still have to do the second IA. Please reply!

[just_a_student]

Hi everyone.

When I use Geogebra to plot my functions, I have to zoom it out to see the graph. However in this case the scale is left too far away , and I actually don't have any axes when I export the image. I tried to rescale, zoom, etc, but it did not work.

Question: is it somehow possible to set my own scales starting from, let's say 190 to 340 and 1930 to 1990?

THANKS A LOT!

[IB>mindf**k]

Hey, I just got my mark for this IA, and I got a 12, so I'm really really sad. I didn't get my actual paper to see what I did wrong, but I'm really depressed now.

So my question is: Is it still possible for me to get a 7 in Math?

My current course mark is a 6, and I still have to do the second IA. Please reply!

Chill man; you need to get 34/40 in the portfolio work (both type 1 and 2) to achieve a 7 in that part of the course, then there is paper 1 and 2, also, a 7 in maths SL is around 79-80 %, so don´t worry

[deraksan]

Hellooo I'm currently working on this portfolio as well and unfortunately it's due on monday and I desperately need some help

1). I know how to find the first equation analytically using matrices, however in order to find the final values for a, b, c, etc. I need to use my calculator (to find the inverse of a 3x3 or 3x4 matrix). Does that count as "using technology" although I'm not supposed to for the analytic part?

2). It asks us to plot the data and the function we came up with on the same set of axes. I know how to plot the data onto excel and onto LoggerPro, and I know how to plot my function/equation on my TI-84 but I can't seem to combine them. Is there a program for PCs which would plot both the set of data and the function I came up with?

Pleeasee help me out I'd really appreciate it!!

Edited January 28, 2012 by deraksan

[~feather~]

Hellooo I'm currently working on this portfolio as well and unfortunately it's due on monday and I desperately need some help

1). I know how to find the first equation analytically using matrices, however in order to find the final values for a, b, c, etc. I need to use my calculator (to find the inverse of a 3x3 or 3x4 matrix). Does that count as "using technology" although I'm not supposed to for the analytic part?

2). It asks us to plot the data and the function we came up with on the same set of axes. I know how to plot the data onto excel and onto LoggerPro, and I know how to plot my function/equation on my TI-84 but I can't seem to combine them. Is there a program for PCs which would plot both the set of data and the function I came up with?

Pleeasee help me out I'd really appreciate it!!

Hi,

1) no, I think it doesn't count as a use of technology because anyway you are doing your own calculations (you are using matrices this time) to find the function. the use of technology is only when you get the whole function by your calculator without doing any calculations yourself.

2) well, I used Autograph. with this program you can put your data points and the equation you created on the same graph.

[opus92fan]

I've been assigned this portfolio and I read through all the posts in this thread. I've noticed that quartic and logarithmic functions have come up a lot. I'm wondering how the same set of data can be interpreted as either quartic or logarithmic. How would you know which one is better?

I'm also kinda confused about the year thing. You convert the years into smaller intergers, but I heard someone say to convert the years back to normal? I currently have 1932 represented as 1, 1936 as 4, 1948 as 12, etc.

Edited January 31, 2012 by opus92fan

[deraksan]

Hellooo I'm currently working on this portfolio as well and unfortunately it's due on monday and I desperately need some help

1). I know how to find the first equation analytically using matrices, however in order to find the final values for a, b, c, etc. I need to use my calculator (to find the inverse of a 3x3 or 3x4 matrix). Does that count as "using technology" although I'm not supposed to for the analytic part?

2). It asks us to plot the data and the function we came up with on the same set of axes. I know how to plot the data onto excel and onto LoggerPro, and I know how to plot my function/equation on my TI-84 but I can't seem to combine them. Is there a program for PCs which would plot both the set of data and the function I came up with?

Pleeasee help me out I'd really appreciate it!!

Hi,

1) no, I think it doesn't count as a use of technology because anyway you are doing your own calculations (you are using matrices this time) to find the function. the use of technology is only when you get the whole function by your calculator without doing any calculations yourself.

2) well, I used Autograph. with this program you can put your data points and the equation you created on the same graph.

Thanks for your help!

[deraksan]

I've been assigned this portfolio and I read through all the posts in this thread. I've noticed that quartic and logarithmic functions have come up a lot. I'm wondering how the same set of data can be interpreted as either quartic or logarithmic. How would you know which one is better?

I'm also kinda confused about the year thing. You convert the years into smaller intergers, but I heard someone say to convert the years back to normal? I currently have 1932 represented as 1, 1936 as 4, 1948 as 12, etc.

Think of them as variations of trend lines. Whichever fits the data best, so it could be whichever function goes through the most points etc., try and experiment with it. Think about the maxs and mins, and where the graph could be headed. I found the program Logger Pro to be extremely helpful.

Sounds like you're on a good track, but don't forget about the additional set of data that's given towards the bottom of the assignment sheet.

Good luck!

[pellytrot]

Hey, I’m very confused with this type II IA.

I have a few questions. I plotted my graph by converting the year values to 1,2,3... against the gold medal height.

My model function is a combination and so there is discontinuity when I plot the different functions.

Am I doing this right? Urgent help needed!

[missymai]

I have a general question on explaining things.

I solved for an equation analytically using matrices and rref. I was just curious as to how much I would have to explain rref and the methods, or is knowledge implied in those sorts of things.

Thanks for any help anyone can give!