baddestwoman Posted November 21, 2011 Report Share Posted November 21, 2011 how so? matrices in what way? i only learned so much with matrices that relating what i know right now doesnt help me in this problem. the only thing i really can solve with matrices is using the reduced row echlon (rref) when but even then i would have to know the coefficients because that only solves for x and y right? i dont understand how using matrices would help, can you explain it? great that you are familiar with rref look at this post --> http://www.ibsurviva...dpost&pid=99521 the context might be different but basically it's asking for the same thing. Thank you so much, im working on the matrices for this data right now, your really helping me out. However later on, the question also asks that i should find another function that models to the data? in your opinion, whats another function besides quartic since thats the one i used, and how may i find it? Reply Link to post Share on other sites More sharing options...
baddestwoman Posted November 21, 2011 Report Share Posted November 21, 2011 Also theres a problem when trying to use matrices, there is no time or im not able to calculate when x = 0, because we're talking about years and there is no obvious pattern to the data so does that matter? or how do i go about this? the data is displayed like this:year | 1932 | 1936 | 1948 | 1952 | 1956 | 1960 | 1964 | 1968 | 1972 | 1976 | 1980 |height| 197 | 203 | 198 | 204 | 212 | 216 | 218 | 224 | 223 | 225 | 236 |(cm)olympic games were not held in 1940 and 1944later on we have to predict 1940 and 1944 anyways. Reply Link to post Share on other sites More sharing options...
dessskris Posted November 21, 2011 Report Share Posted November 21, 2011 I have the data and the task paper, don't worry. sorry for not explaining in advance. you need to convert the year values into small integers like 0, 1, 2, 3 and so on and so forth (hint: horizontal stretch and translation), then your function needs to be expressed back in terms of the real years. you cannot use the real year values because you'll get an error. yeah there's no obvious pattern, I also wonder why. screw whoever made the task paper!! after this you're asked to use technology for your second function, right? just try all the models and choose the one you think fits best (lol ) but of course don't mention that you actually tried every single function, just say you chose this function because blah blah blah and it fits the data well, etc Reply Link to post Share on other sites More sharing options...
vivesta Posted November 21, 2011 Report Share Posted November 21, 2011 still so confused about this SL, i've read all these posts like multiple times and no help. Alright so i plotted the data on a graph and i'm deciding to go with quartic function, what now? how do i make an equation related to this data? im just looking for a,b,c,d and e right? how do i do this?!use matrices.how so? matrices in what way? i only learned so much with matrices that relating what i know right now doesnt help me in this problem. the only thing i really can solve with matrices is using the reduced row echlon (rref) when but even then i would have to know the coefficients because that only solves for x and y right? i dont understand how using matrices would help, can you explain it?if we havent been taught matrices the topic... then there must be another way riiight? Reply Link to post Share on other sites More sharing options...
vivesta Posted November 21, 2011 Report Share Posted November 21, 2011 I have the data and the task paper, don't worry. sorry for not explaining in advance. you need to convert the year values into small integers like 0, 1, 2, 3 and so on and so forth (hint: horizontal stretch and translation), then your function needs to be expressed back in terms of the real years. you cannot use the real year values because you'll get an error. yeah there's no obvious pattern, I also wonder why. screw whoever made the task paper!! after this you're asked to use technology for your second function, right? just try all the models and choose the one you think fits best (lol ) but of course don't mention that you actually tried every single function, just say you chose this function because blah blah blah and it fits the data well, etc 'i have tried out 2 different graphs on excel.. and one fits the data really well but it is obvious that it wont work for future prediction of data whereas the other graph doesn't fit as well though it has a limitation and therefore more suitable for this which one will 'fit best'... jst taking opinions Reply Link to post Share on other sites More sharing options...
baddestwoman Posted November 21, 2011 Report Share Posted November 21, 2011 I have the data and the task paper, don't worry. sorry for not explaining in advance. you need to convert the year values into small integers like 0, 1, 2, 3 and so on and so forth (hint: horizontal stretch and translation), then your function needs to be expressed back in terms of the real years. you cannot use the real year values because you'll get an error. yeah there's no obvious pattern, I also wonder why. screw whoever made the task paper!! after this you're asked to use technology for your second function, right? just try all the models and choose the one you think fits best (lol ) but of course don't mention that you actually tried every single function, just say you chose this function because blah blah blah and it fits the data well, etc there must be a problem with what im doing, i did the whole matrices procedure and it came up not even looking right on the graph, completely no where near the data. ugh i seriously give up. Reply Link to post Share on other sites More sharing options...
dessskris Posted November 21, 2011 Report Share Posted November 21, 2011 if we havent been taught matrices the topic... then there must be another way riiight?yeah but you'll have less options. you will only be able to do like quadratic, cubic, exponential, log, etci have tried out 2 different graphs on excel.. and one fits the data really well but it is obvious that it wont work for future prediction of datawhereas the other graph doesn't fit as well though it has a limitation and therefore more suitable for thiswhich one will 'fit best'... jst taking opinionsI'd prefer the one that fits better actually.there must be a problem with what im doing, i did the whole matrices procedure and it came up not even looking right on the graph, completely no where near the data. ugh i seriously give up.when is this due? if not tomorrow, I could help you fix your matrices. message me if you want and I will give you my email address. Reply Link to post Share on other sites More sharing options...
Hedda Posted November 22, 2011 Report Share Posted November 22, 2011 (edited) I'm currently working on this task but due to time limits it's coming out a bit iffy... I have two main problems: 1)The last sentence of the task "What modifications, if any, need to be made to your model to fit the new data?" - implies that your model would function well (or okay) with the new data? The thing is, I was planning on completely scrapping the model I have the in the beginning (which fits the values of that part of the task though) and go for a different one for all the values. Do you think this could be an okay way to go about it, or will the examiner punish me for changing it too much? 2) Is it possible to analytically create a logarithmic function with the values given in this task? If so, how do one go about doing this? (Not asking for specific answer for just this task, but a general way to create one) Edited November 22, 2011 by Hedda Reply Link to post Share on other sites More sharing options...
URA BOAT Posted November 22, 2011 Report Share Posted November 22, 2011 The last sentence of the task "What modifications, if any, need to be made to your model to fit the new data?" - implies that your model would function well (or okay) with the new data? The thing is, I was planning on completely scrapping the model I have the in the beginning (which fits the values of that part of the task though) and go for a different one for all the values. Do you think this could be an okay way to go about it, or will the examiner punish me for changing it too much?i think that is what the question is asking. your first function only fits the first set of data, and that is swell but upon the addition of the second set you will and should(unless your first formula was perfect) notice that your previous line dose not fit anymore. that is what this thing is asking. Reply Link to post Share on other sites More sharing options...
dessskris Posted November 23, 2011 Report Share Posted November 23, 2011 I'm currently working on this task but due to time limits it's coming out a bit iffy... I have two main problems: 1)The last sentence of the task "What modifications, if any, need to be made to your model to fit the new data?" - implies that your model would function well (or okay) with the new data? The thing is, I was planning on completely scrapping the model I have the in the beginning (which fits the values of that part of the task though) and go for a different one for all the values. Do you think this could be an okay way to go about it, or will the examiner punish me for changing it too much? 2) Is it possible to analytically create a logarithmic function with the values given in this task? If so, how do one go about doing this? (Not asking for specific answer for just this task, but a general way to create one) if your model is already awesome, you don't need to make any modification. if it's just okay, you may want to make some changes. if it's VERY horrible, restart modelling the whole thing. yes you can. start with the general formula: y=a*ln(x)+b then, pick two points you want to use. then, substitute the values of x and y, then solve for a and b simultaneously. however, I'm not sure how well a logarithmic function could fit. it depends on which points you're choosing! Reply Link to post Share on other sites More sharing options...
CamelCup Posted November 23, 2011 Report Share Posted November 23, 2011 we are also doing this IA and some people in my class told me to use cubic function Reply Link to post Share on other sites More sharing options...
c.xie Posted November 25, 2011 Report Share Posted November 25, 2011 What exactly does it mean when it says to "analytically create an equation to model the data"? Does it mean that I have to do actual math, or is calculator work okay? Reply Link to post Share on other sites More sharing options...
dessskris Posted November 25, 2011 Report Share Posted November 25, 2011 What exactly does it mean when it says to "analytically create an equation to model the data"? Does it mean that I have to do actual math, or is calculator work okay?analytically=algebraically=mathematicallyso yeah you have to do actual maths, do lots of working and calculation to get a function.you CANNOT use a calculator to just find the best regression in this part. this is asked for the next part. Reply Link to post Share on other sites More sharing options...
vivesta Posted November 26, 2011 Report Share Posted November 26, 2011 how many analytical and regression models should i test, recommended wise i know there isn't a 'correct' number but just would like to know an approximate so i don't overdo or underdo by too muchthanks!! Reply Link to post Share on other sites More sharing options...
dessskris Posted November 26, 2011 Report Share Posted November 26, 2011 how many analytical and regression models should i test, recommended wise i know there isn't a 'correct' number but just would like to know an approximate so i don't overdo or underdo by too muchthanks!!you're only asked to create 3 models:1. one analytically for the data from the first table2. one technologically for the data from the first table3. one modified from either function 1 or 2 for the data from the second tableso, the answer to your question is one by hand and one from calculator. Reply Link to post Share on other sites More sharing options...
URA BOAT Posted November 26, 2011 Report Share Posted November 26, 2011 What exactly does it mean when it says to "analytically create an equation to model the data"? Does it mean that I have to do actual math, or is calculator work okay?analytically=algebraically=mathematicallyso yeah you have to do actual maths, do lots of working and calculation to get a function.you CANNOT use a calculator to just find the best regression in this part. this is asked for the next part.ok i can't seem to get it...im using the logistic function and i can't seem to get it... Reply Link to post Share on other sites More sharing options...
dessskris Posted November 26, 2011 Report Share Posted November 26, 2011 you want to model a logistic function analytically??? I myself don't think I could do it either... you know, some functions are just too difficult to model analytically. choose another function? sorry for being unhelpful this time! 1 Reply Link to post Share on other sites More sharing options...
Salve Posted November 26, 2011 Report Share Posted November 26, 2011 how do you use Geogebra for points and then add a quartic line? Reply Link to post Share on other sites More sharing options...
URA BOAT Posted November 26, 2011 Report Share Posted November 26, 2011 open Geogebraclick on "view"select "spreadsheet"insert your values highlight the data the you what to graphbelow the view bottom their will be a box that has a graph on it, click on a little arrow that is pointing down in that boxselect the graph that has scatter plot like graph with a red line going thou ita new window should appear, this window will have points plottedin the lower left corner their will be a option box where you can pick your equation.play around with it...their are many thing this thing can do!!! Reply Link to post Share on other sites More sharing options...
vivesta Posted November 27, 2011 Report Share Posted November 27, 2011 i think i have entered the regression model equation wrong on excel... for the future prediction bits though the values all seem close and rightwill teachers type in our models and check them all?! Reply Link to post Share on other sites More sharing options...
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