moneyfaery Posted February 8, 2009 Report Share Posted February 8, 2009 Power of 8? Wtf... I haven't done this portfolio as I'm HL, however I just quickly plotted the points and found a quadratic regression that fit the data to r2=0.9998. I'd say that's pretty damn accurate. Also, at x=0, f(x)=0 (approx), I'm not sure if this is how it's supposed to be? Reply Link to post Share on other sites More sharing options...
hazemm Posted February 8, 2009 Report Share Posted February 8, 2009 (edited) Power of 8? Wtf... I haven't done this portfolio as I'm HL, however I just quickly plotted the points and found a quadratic regression that fit the data to r2=0.9998. I'd say that's pretty damn accurate. Also, at x=0, f(x)=0 (approx), I'm not sure if this is how it's supposed to be?I already found a quadratic function and cubic function, but there is a seperate question, which asks to find a polynomial, which passes through all the points. My math teacher says that a cubic and quadratic function do not as the R-squared value isn't one. Also, i think y=0 when x=0 because if there was a guide at the tip, lets number it zero, then its distance would be zero cm from the tip. Edited February 8, 2009 by hazemm Reply Link to post Share on other sites More sharing options...
raj2y Posted February 9, 2009 Report Share Posted February 9, 2009 Hey! I have a math portfolio in Math SL about fishing rods and its guides.There are 8 guides, 9 including the guide on the tip of the rod. The values are given below:The total length of the fishing rod (Leo's) is 230 cm.I have diffeculties understanding what "define suitable variables" means. Could i have any pointers?Thank you! Reply Link to post Share on other sites More sharing options...
hazemm Posted February 9, 2009 Report Share Posted February 9, 2009 (edited) Hey guys,I'm at the last part of the task where it asks you to use your quadratic model to fit the new data regarding Marks 300 cm fishing rod.Guide number (from tip) 1 2 3 4 5 6 7 8Distance from the tip (cm) 10 22 34 48 64 81 102 124how can I change my function in order to make it fit the data better, so that I can explain how I did it. Cheers,Hazem Edited March 8, 2009 by deissi Reply Link to post Share on other sites More sharing options...
deissi Posted February 9, 2009 Report Share Posted February 9, 2009 It won't be the power of eight either, but you're getting close. Remember, the origin is not a given data point. Reply Link to post Share on other sites More sharing options...
hazemm Posted February 9, 2009 Report Share Posted February 9, 2009 well I think i got it, it was very close to the power of 8, i just didnt consider the orgin.Also, in general, when discussing the implication of guides you should consider the orgin, and if your using regression to back up any of the function you found algebraically because it models the true nature of the situation, otherwise your model will not be useful when extending it to other values eg. adding guides. Reply Link to post Share on other sites More sharing options...
moneyfaery Posted February 9, 2009 Report Share Posted February 9, 2009 Well, since this seems to be a probability-based portfolio, you're going to need to define a random variable. Presumably, you will also need to come up with some kind of formula to model the data. (I haven't looked at the portfolio, so I'm just guessing here ) Definining suitable variables refers to explicitly stating your variables for your model(s) - don't assume the examiner will know otherwise because your random variable may be different from someone else's. This is in addition to it being good mathematical practice. Reply Link to post Share on other sites More sharing options...
raj2y Posted February 9, 2009 Report Share Posted February 9, 2009 hey! im so sorry. Since you havent seen it, it may be confusing.This is the portfolio. I am suppose to be using matrices, etc to find a quadratic and a cubic function. I have all the information, and i know how to do everything. I am just having problems with defining the suitable variables and discussing parameters/constraints.Could anyone guide me in the right direction?THANKS in advance=) Reply Link to post Share on other sites More sharing options...
moneyfaery Posted February 9, 2009 Report Share Posted February 9, 2009 Ah, I see, so it's not a probability-based portfolio like I thought. Looks simple enough. Define suitable variables, discuss parameters/contraints.This is a MODEL. That is, there are basic assumptions about the data. What are these assumptions and/or limitations?Using technology, plot the data points on a graph.There, it even answered it for you. What variables are you plotting the data by? Reply Link to post Share on other sites More sharing options...
raj2y Posted February 10, 2009 Report Share Posted February 10, 2009 How long is your portfolio, if i may ask? =)Im scared that mine isnt long enough.Thanks=)Hey guys,I'm at the last part of the task where it asks you to use your quadratic model to fit the new data regarding Marks 300 cm fishing rod.When i graph the function with the new data points, it doesn't fit at all. My equation is nd the new points are:Guide number (from tip) 1 2 3 4 5 6 7 8Distance from the tip (cm) 10 22 34 48 64 81 102 124how can I change my function in order to make it fit the data better, so that I can explain how I did it.Cheers,Hazem Reply Link to post Share on other sites More sharing options...
Aether Posted February 11, 2009 Report Share Posted February 11, 2009 (edited) Almost at the end of the portfolio they ask you to get the implications for adding a 9th ring. Obviously to know this you must know where the 9th ringlet is located, is this helpful in any other thing in the portfolio or just info. you will be using to answer this one question? Edited February 11, 2009 by Aether Reply Link to post Share on other sites More sharing options...
Teddy_The_Bear Posted March 8, 2009 Report Share Posted March 8, 2009 haha mine is due 2mo...im nearly done i got 800 words so far...im assuming 1000 will be the final Reply Link to post Share on other sites More sharing options...
deissi Posted March 8, 2009 Report Share Posted March 8, 2009 haha mine is due 2mo...im nearly done i got 800 words so far...im assuming 1000 will be the final?? mine was over 4,000 words. Reply Link to post Share on other sites More sharing options...
Mahuta ♥ Posted March 8, 2009 Report Share Posted March 8, 2009 What?? 1000 words only ? lol..should I say lucky?I dont see how i can explain and justify enough with 1000 words only Reply Link to post Share on other sites More sharing options...
Hedron123 Posted March 8, 2009 Report Share Posted March 8, 2009 Hazem, the quadratic equation you modelled for Leo's rod will definitely NOT fit Mark's rod as they are different rods (meaning that the guides are arranged with a different criteria). That is actually one of the limitations of the portfolio, your model is not universal and it will serve only for Leo's rod. As regards the word count, I've done over 4000 words also and I think 1000 is a bit short to explain everything. Defining variables means clearly stating which is the dependent and the independent variable (you might want to give them a name). Reply Link to post Share on other sites More sharing options...
Teddy_The_Bear Posted March 26, 2009 Report Share Posted March 26, 2009 (edited) ?? mine was over 4,000 words.Lawl dude, if u ask me math portfolios should be less in writing, i hv a crap load of equations though that didnt get included into the wordcount and a crapload of graphs. i think i did pretty and couldnt think of getting anymore in there..im usually a 5-6 student for math so its aight.gonna get it next week i guess so lets see, will update when i get my grade ^^. oh and final was 13-- words =P, spanning 12 pages Edited March 26, 2009 by Teddy_The_Bear Reply Link to post Share on other sites More sharing options...
Sandwich Posted March 26, 2009 Report Share Posted March 26, 2009 Lawl dude, if u ask me math portfolios should be less in writing, i hv a crap load of equations though that didnt get included into the wordcount and a crapload of graphs. i think i did pretty and couldnt think of getting anymore in there..im usually a 5-6 student for math so its aight.gonna get it next week i guess so lets see, will update when i get my grade ^^. oh and final was 13-- words =P, spanning 12 pagesWell as Type II are all experimental as relates to real life, the more explanation of how your model fits real life the better (:Definitely when it comes to explaining the processes you go through and why you're doing things you should explain all of your working and calculations fully. With fishing rods, it also helps to actually talk about a fishing rod itself to begin with, to set the scene, as it were. All adds into showing you understand all about application of the model.You get marks for writing, is pretty much what I'm trying to say! Reply Link to post Share on other sites More sharing options...
lennonlives Posted April 4, 2009 Report Share Posted April 4, 2009 So, I was reading all of these posts, and they've helped me a lot to get where I am on the portfolio, but I still don't understand the part where they want us to give a polynomial function that includes all points. I read something about needing to factor the poin (0,0) into the function? I just spent a long time making an 8 variable equation and it didn't work, so if anyone could PLEASE clear up what I'm doing wrong that would be greatly appreciated.. 1 Reply Link to post Share on other sites More sharing options...
deissi Posted April 4, 2009 Report Share Posted April 4, 2009 Apparently you're doing the equation wrong. You're on the right track.You should consider the zero point but it should not be plotted. Reply Link to post Share on other sites More sharing options...
Tilia Posted May 1, 2009 Report Share Posted May 1, 2009 (edited) QuestionsCould anyone give me any hints about the "suitable variables, parameters and constraints"?Do I have to find the polynomial function manually?What do they mean with "choice of function"?The last function, can it be any function?I'm going mad about this portfolio... Edited May 2, 2009 by Tilia Reply Link to post Share on other sites More sharing options...
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