IA Type II -- Gold Medal Heights

[Paige Closson]

My teacher told me that matrices can be used I this is to find the function. How do I do matrices with in this problem!

[devdav]

okay... I am planning on doing a cubic graph for the portion that has to be done by hand, then a natural log graph after I can use technology. Is anyone else using those two graphs?

[Dramatic Pancake]

Has anyone's own model actually worked for all of the points? When I create a model using matrices it creates a graph that revolves around the coordinates I've selected and doesn't accurately reflect for every single one of the years.

So like. My cubic function..isn't accurate outside of 4 selected x,y coordinates

[momotranxx]

hihi

i tried using the matrices method and i have learned about it in class but my only problem is that my resulting formula isn't working out, when i graphed it, it was nothing like a curve..at all and i think it has something to do with the fact that i changed the actual years into smaller numbers to work with but i'm not sure..help please! and thank you!

[Aleth Antonia]

The main problem for me is my lack of math vocabulary on this IA... I understand what a constraint is but what is a parameter?

When it asks for new set of axes, its asking to do it in your program again or does it have to be hand drawn?

[thebest]

uhh.. are we supposed to put a domain for the first graph where you make ur own function, so the domain would be the first data in the data and last date in the data?

[dessskris]

My teacher told me to do trial and error for each variable like a,b, and c to find the equation for a function. is this a valid method to finding the function analytically?

no it is not

OK the first data plot I found to be cubic

But how do I write the intro and conclusion to it...?

I saw examples with BMI where they just explain what BMI is and stuff but I cannot write an intro

open the Mathematics forum, you see a thread called Portfolio Tips? check that out.

Thanks, I'm not sure how you were offended since I was simply asking someone to state what is the correct notation. Like U(n) for series and sequences...I apologize though.

I was not offended. your question was just ridiculous, stating all the notations in this IA?? there are many! and for god's sake isn't it just common sense?

Has anyone's own model actually worked for all of the points? When I create a model using matrices it creates a graph that revolves around the coordinates I've selected and doesn't accurately reflect for every single one of the years.

So like. My cubic function..isn't accurate outside of 4 selected x,y coordinates

of course your model will only pass through several points, not all.

hihi

i tried using the matrices method and i have learned about it in class but my only problem is that my resulting formula isn't working out, when i graphed it, it was nothing like a curve..at all and i think it has something to do with the fact that i changed the actual years into smaller numbers to work with but i'm not sure..help please! and thank you!

you were supposed to convert the year values into small integers, but after that don't forget to convert it back to the original year values in your function. remember stretching and translation? got something to do with the x value? basically it's just like that.

The main problem for me is my lack of math vocabulary on this IA... I understand what a constraint is but what is a parameter?

When it asks for new set of axes, its asking to do it in your program again or does it have to be hand drawn?

parameter is just like a constant

every graph should be done through a graphing software, not hand drawn.

uhh.. are we supposed to put a domain for the first graph where you make ur own function, so the domain would be the first data in the data and last date in the data?

no, because you'll be asked to use your graph to predict the future trend.

[barneystinsonforlife]

momotranxx, on Dec 15, 2011 - 01:15, said:

hihi

i tried using the matrices method and i have learned about it in class but my only problem is that my resulting formula isn't working out, when i graphed it, it was nothing like a curve..at all and i think it has something to do with the fact that i changed the actual years into smaller numbers to work with but i'm not sure..help please! and thank you!

you were supposed to convert the year values into small integers, but after that don't forget to convert it back to the original year values in your function. remember stretching and translation? got something to do with the x value? basically it's just like that.

hi! thanks so much for all your help on this ia! I understand that you have to convert the year values into smaller integers, but I do not fully understand when you are supposed to convert them back to the original year values. thank you!

[stellarhelp]

Do we have to graph the cubic regression line using excel?

I have mac excel 2011 and I've spent two days trying to get a cubic regression on my graph. Is the cubic regression line required (using excel)? Or could I draw it by hand?

[aidan54321]

i just created an account on this website so I could see this page. I'm working on this project right now.

I'm thinking a logarithmic function should work best, because the heights cannot continue to grow indefinitly, due to the limitations of human physiology... right? The problem is that my TI 84 Plus gives me a domain error when I try and graph a logistic, exponential, or power regretion with the data. Is logistic the same as logarithmic?

[bensmends]

my teacher said it might be logarithmic, and this seems to make sense considering the natural limits of the high jump event (can't jump infinitely high, etc.), but I can' quite get the algebra. How would you cancel out a variable in a simultaneous equation when everything is multiplied?

[Vicki Marie]

Hey can someone help me? I found the trendline in excel, and it gave me an equation (y=-0.0008x^3 + 4.7837x^2 - 9390.2x + 6E+06)

Does anyone know how to create a table in excel based on that equation?

[dessskris]

hi! thanks so much for all your help on this ia! I understand that you have to convert the year values into smaller integers, but I do not fully understand when you are supposed to convert them back to the original year values. thank you!

once you get the function.

Do we have to graph the cubic regression line using excel?

I have mac excel 2011 and I've spent two days trying to get a cubic regression on my graph. Is the cubic regression line required (using excel)? Or could I draw it by hand?

no, excel sucks. use Autograph, or Geogebra.

i just created an account on this website so I could see this page. I'm working on this project right now.

I'm thinking a logarithmic function should work best, because the heights cannot continue to grow indefinitly, due to the limitations of human physiology... right? The problem is that my TI 84 Plus gives me a domain error when I try and graph a logistic, exponential, or power regretion with the data. Is logistic the same as logarithmic?

perhaps you could try other graphing softwares. no, logistic and logarithmic are completely different.

my teacher said it might be logarithmic, and this seems to make sense considering the natural limits of the high jump event (can't jump infinitely high, etc.), but I can' quite get the algebra. How would you cancel out a variable in a simultaneous equation when everything is multiplied?

perhaps you could bring stuff over to the other side, and use logs?

Hey can someone help me? I found the trendline in excel, and it gave me an equation (*********)

Does anyone know how to create a table in excel based on that equation?

don't post your equation here. no please don't use excel for this. it's not recommended. use Autograph or Geogebra, or your TI or any other graphing software.

[barneystinsonforlife]

I am having a bit of trouble when doing the regressions in my calculator. I know the steps and all, but I am just confused with whether or not I should just insert 1932, 1936, 1948 and so on into the list and exclude 1940 and 1944 altogether. I know that seems dumb, but I'm just so afraid of doing the wrong thing. Thank you to everyone for all their help!

[Marija Vaitkevi�ienė]

I am having a bit of trouble when doing the regressions in my calculator. I know the steps and all, but I am just confused with whether or not I should just insert 1932, 1936, 1948 and so on into the list and exclude 1940 and 1944 altogether. I know that seems dumb, but I'm just so afraid of doing the wrong thing. Thank you to everyone for all their help!

Am, I believe you are meant to find out that when you get the regression, am I right? Like, you'll find these values afterwards, when you'll search for f(1940) and f(1944).

Ah, Desy, what would we do without you? Its a second time I'm coming back to you, my fairy godmother!

My teacher suggested to find 11th power regression, which would definitely fit all of the given points in the first part. The problem is, I don't get such beauty as you did . I get only 2 cols with indefinite fractions and two 0 cols at the back...

So, I guess I better go back to exp? Though I did like the idea of logarithmic - really, you cant jump to infinity. That's part of the limitations, I suppose. That one was a good point, really.

[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!!!!!

[Vicki Marie]

Hey can someone help me? I found the trendline in excel, and it gave me an equation (*********)

Does anyone know how to create a table in excel based on that equation?

don't post your equation here. no please don't use excel for this. it's not recommended. use Autograph or Geogebra, or your TI or any other graphing software.

THANKS!!!! my teacher says we must prove algebraic curve fitting. do you have any idea how I would approach this? I know if it was linear, but I want to do a quartic equation

Edited December 30, 2011 by Vicki Marie

[dessskris]

I am having a bit of trouble when doing the regressions in my calculator. I know the steps and all, but I am just confused with whether or not I should just insert 1932, 1936, 1948 and so on into the list and exclude 1940 and 1944 altogether. I know that seems dumb, but I'm just so afraid of doing the wrong thing. Thank you to everyone for all their help!

include only the given points that you know the coordinates.

Ah, Desy, what would we do without you? Its a second time I'm coming back to you, my fairy godmother!

My teacher suggested to find 11th power regression, which would definitely fit all of the given points in the first part. The problem is, I don't get such beauty as you did . I get only 2 cols with indefinite fractions and two 0 cols at the back...

So, I guess I better go back to exp? Though I did like the idea of logarithmic - really, you cant jump to infinity. That's part of the limitations, I suppose. That one was a good point, really.

aww lol you can do it!

uhm I don't really get what you did wrong. perhaps you meant some of the constants in the equation turned out to be 0? that's fine. e.g. we can always have where the coefficient of x^2 is 0.

it's up to you what function you want to choose, really. one thing though, if your teacher strongly disagrees on your choice of function, they might not give you the mark. they already told you what function you should use, so it looks like they have their personal choice and usually teachers like this don't approve of functions outside of their suggestions. well if your teacher is a bit nicer then you're good. on the other hand, though, when submitting the IA to the IB moderators, your teacher will have to submit their own work too. and if everyone in your class is modelling 10th poly and all the IAs that are sent use that function, then your school/teacher will be in a trouble, because it'll be obvious that your teacher told the students what function to model (which they're not supposed to do).

just some info for you to think about.

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.

THANKS!!!! my teacher says we must prove algebraic curve fitting. do you have any idea how I would approach this? I know if it was linear, but I want to do a quartic equation

prove...as in prove the equation or prove the function choice? with function choice you can discuss its characteristics, like stationary points or inflexion points...or anything you can discuss really. but if it's the equation, the best thing you can do is to find the R^2 value.

thanks for quoting btw, otherwise i probably would take weeks to get back to you

[Indre]

_{I'm also doing the same task and I found that polynomial function of ax^9+bx^8+... suits all the data points! However, my GDC can't find the constants a,b,c... by using the matrix method. But I can write down the equation the GeoGebra gives. Is it an appropriate way of "use of technology" for the question "use technology to find another function that models the data"? Or am I supposed to use my GDC only for this question?}

_{And the last inquiry: since both cubic and 9th degree functions are polynomial functions, am I still able to model the cubic function for my "analytical" modelling, and 9th degree - for the technological one?}

_{Thanks a lot!}

[thebest]

_{I'm also doing the same task and I found that polynomial function of ax^9+bx^8+... suits all the data points! However, my GDC can't find the constants a,b,c... by using the matrix method. But I can write down the equation the GeoGebra gives. Is it an appropriate way of "use of technology" for the question "use technology to find another function that models the data"? Or am I supposed to use my GDC only for this question?}

_{And the last inquiry: since both cubic and 9th degree functions are polynomial functions, am I still able to model the cubic function for my "analytical" modelling, and 9th degree - for the technological one?}

_{Thanks a lot!}

For use of technology, you can use your GDC, Excel, or any other program software to get a technology function.

And for us, we could choose any function to analytically model it, and another (perhaps completley different) function to technlogically model it.