sk2801 Posted December 11, 2011 Report Share Posted December 11, 2011 how do i graph a logistic function on geogebra i'd appreciate anyone who can get back asap!! thanks SK!! its your azn buddy...hahah did you put it in the input box below? lol so i input the equation into the input box???? hope that works! Reply Link to post Share on other sites More sharing options...
Wishes Posted December 11, 2011 Report Share Posted December 11, 2011 Hey everyone, when it says "what types of functions could model the behaviour of the graph" how many different types of functions should i show? also, can i still use logistic as one model function even though it's given later in the assignment? i'd appreciate any help or advice on this thank youuuuuu! You just need to name a couple, and give reasons why they would work. And no, you can't use logistic, that's for the later bit how do i graph the logistic function on excel??!?!?!?!?! if not, are there any other graphing softwares i can use ????????? someone reply asap! please! You can't graph it on Excel sadly... but try GeoGebra, it works great! for the graphs, can i name cubic and quartic, and describe the pros and cons? also, i was planning to do exponential and logistic. if i cant include logistic anymore, should i just stop with exponential and keep that as my main graph? thanks once again Yeah you can name them, and talk about why you think they would model the data well (like how it curves like an S shape, similar to cubics). The thing is... exponential really isn't very good at all. Have you tried graphing exponential and different polynomials? When I did this, cubic and quartic and higher degree polynomials were much better fits for the data, so I wouldn't use exponential as your "main graph". Good luck! I tried to use quartic and cubic as well, but they plummeted down before the 9th and 10th point. Did you use the matrices to find your equations or some other method? i used regression to find my equations...............thats why i think cubic might not be the best fit, and exponential might be better im not quite sure anymore.. what do u mean by plummeted? did you substitute the points back into the equation to double check? When I graph the equation of the line of best fit (in this case a quartic regression) ontop of my original data, the line will follow the trend of the data points (i.e. increasing) and then all of a sudden shots down (i.e. decreases rapidly) once it passes the 8th point. I`ve spent my entire day trying to figure this out and im lost. Somebody please tell me what im doing wrong!! Reply Link to post Share on other sites More sharing options...
sk2801 Posted December 11, 2011 Report Share Posted December 11, 2011 HELPP! I'm really lost with Geogebra! I want the axes to show up till 1995! but the graph turns out to be REALLY small! any help or advice on how to work Geogebra would be EXTREMELY HELPFUL!!!! someone pls reply asap Thank you soooooooooooooo much! Reply Link to post Share on other sites More sharing options...
Wishes Posted December 11, 2011 Report Share Posted December 11, 2011 Also, Im trying to put in values for the k l and m parameters, but i keep getting a straight horizantal line on my calculator (TI-83 graphing calc) and Im not sure why Im not getting a proper logistic curve I know what the variables are suppose to represent, i just cant seem to find the right values. Is it okay for me to ask if someone knows the ranges for the values,(e.g. K> B (?) ) ? that will make my curve, curve properly and not be a straight horizatal line Reply Link to post Share on other sites More sharing options...
hanaar Posted December 11, 2011 Report Share Posted December 11, 2011 Hello. Just a quick question for "Analytically develop one model function that fits the data points on your graph.".If "Analytically" means algebraically, you cannot use your GDC and Wolfram Alpha at all?Or can I use my calculator to solve my simultaneous equation?because it seems really difficult to solve it only by hand. Reply Link to post Share on other sites More sharing options...
sk2801 Posted December 11, 2011 Report Share Posted December 11, 2011 Hello to everybody! I am nearly finished with this one, only wondering whether it is better to include graphs that show grids or ones that do not. Does that makes any difference whatsoever? HEYYY! what program did u use to graph ur graphs? it would be very very useful if you cud tell me the software thanks Reply Link to post Share on other sites More sharing options...
bomaha Posted December 11, 2011 Report Share Posted December 11, 2011 how can you prove that the function could be an exponential function? Is there a specific characteristic of exponential functions that the graph follows? You don't have to prove that it's an exponential function (actually exponential isn't that good). But if you had your mind set on exponential, the first half of the data points come close to an exponential. I recommend looking at a polynomial... cubic or higher degree! Good luck! Thanks! I now realize exponential's not the best. So, I'm using cubic for my model. When they say "analytically develop one model function", can we use regression to find the equation or do we have to use matrices? If its matrices, I'm screwed because I don't understand it Analytically means algebraically so you can't use technology i.e regression. You need to a number of equations and solve it using matrices. Study your textbook or ask your teacher about matrices. The matrices techniques applied here are very basic. Reply Link to post Share on other sites More sharing options...
HoolaBaloola Posted December 11, 2011 Report Share Posted December 11, 2011 Hey everyone, when it says "what types of functions could model the behaviour of the graph" how many different types of functions should i show? also, can i still use logistic as one model function even though it's given later in the assignment? i'd appreciate any help or advice on this thank youuuuuu! You just need to name a couple, and give reasons why they would work. And no, you can't use logistic, that's for the later bit how do i graph the logistic function on excel??!?!?!?!?! if not, are there any other graphing softwares i can use ????????? someone reply asap! please! You can't graph it on Excel sadly... but try GeoGebra, it works great! for the graphs, can i name cubic and quartic, and describe the pros and cons? also, i was planning to do exponential and logistic. if i cant include logistic anymore, should i just stop with exponential and keep that as my main graph? thanks once again Yeah you can name them, and talk about why you think they would model the data well (like how it curves like an S shape, similar to cubics). The thing is... exponential really isn't very good at all. Have you tried graphing exponential and different polynomials? When I did this, cubic and quartic and higher degree polynomials were much better fits for the data, so I wouldn't use exponential as your "main graph". Good luck! I tried to use quartic and cubic as well, but they plummeted down before the 9th and 10th point. Did you use the matrices to find your equations or some other method? i used regression to find my equations...............thats why i think cubic might not be the best fit, and exponential might be better im not quite sure anymore.. what do u mean by plummeted? did you substitute the points back into the equation to double check? When I graph the equation of the line of best fit (in this case a quartic regression) ontop of my original data, the line will follow the trend of the data points (i.e. increasing) and then all of a sudden shots down (i.e. decreases rapidly) once it passes the 8th point. I`ve spent my entire day trying to figure this out and im lost. Somebody please tell me what im doing wrong!! As i said! That usually happens when you pick x and y values that are too close to each other, this can be fixed by taking x and y values that are largely separate from each other e.g. dont take x values 0,5,15,20!! rather you should widen your choice Reply Link to post Share on other sites More sharing options...
tbhizzle Posted December 11, 2011 Report Share Posted December 11, 2011 I'm doing this today, and have been since 8am. I'm only on the analytical development of my exponential function that seems to best fit the data (eventhough a logisitc function is most reasonable in the situation). Anyway, how am I supposed to do this without my calculator??? should I plug a set of data points into a^x+b and solve for a and b???yep that is what i did, but be warned that it will only go through the points u used to find it so it will be different from what you would get if you used a calculator to find it. so just solve it like a system of equations. Hope that helps!! 1 Reply Link to post Share on other sites More sharing options...
member101 Posted December 11, 2011 Report Share Posted December 11, 2011 so I've made my graph of the function that fits the data (it's exponential) and put it on the same axes as the original data. It's way off... it only passes through 1 point, and the last part says to revise your model if neccessary. Does that mean I need to make a new model? Reply Link to post Share on other sites More sharing options...
q1w2e3r4 Posted December 11, 2011 Report Share Posted December 11, 2011 Hi, I am trying to curretly figure out the Parameter, K L M and with my ti-84's regression, however I am getting wierd values whwn I do Logisitc regression. When I graph the function it gives me, its more like a lin and it misses like 3 points, any ideas? Or is it supposed to be like that? Reply Link to post Share on other sites More sharing options...
Wishes Posted December 12, 2011 Report Share Posted December 12, 2011 so I've made my graph of the function that fits the data (it's exponential) and put it on the same axes as the original data. It's way off... it only passes through 1 point, and the last part says to revise your model if neccessary. Does that mean I need to make a new model?my friend was doing exponential. when she was typing it into the program she said she wasn't getting it touching any of the points at first to. you have to make sure you have brackets in all of the right places, and well (depending on the program you are using to graph) you may have to use x instead of t. I would double check points, decimals (i.e. if you put 00 instead of 0.0) , and the actual equation (the way you put it in the calc). hope it helps. Reply Link to post Share on other sites More sharing options...
Wishes Posted December 12, 2011 Report Share Posted December 12, 2011 Hello to everybody! I am nearly finished with this one, only wondering whether it is better to include graphs that show grids or ones that do not. Does that makes any difference whatsoever? HEYYY! what program did u use to graph ur graphs? it would be very very useful if you cud tell me the software thanks download "Graph" heres the link for PCs http://download.cnet.com/Graph/3000-2053_4-10063417.html its an awesome and invaluble tool. just figet a bit with axis (double cleck on the tab on the left that says axis to edit them) Reply Link to post Share on other sites More sharing options...
Akayuki + Lucifel Posted December 12, 2011 Report Share Posted December 12, 2011 Hello to everybody! I am nearly finished with this one, only wondering whether it is better to include graphs that show grids or ones that do not. Does that makes any difference whatsoever? HEYYY! what program did u use to graph ur graphs? it would be very very useful if you cud tell me the software thanks download "Graph" heres the link for PCs http://download.cnet...4-10063417.html its an awesome and invaluble tool. just figet a bit with axis (double cleck on the tab on the left that says axis to edit them) It really IS invaluable, takes some time to get used to but the functions are alright. Another good tool, should you ever be in need of a TI-substitute: http://www.microsoft.com/education/ww/products/Pages/mathematics-4.0.aspx Reply Link to post Share on other sites More sharing options...
sk2801 Posted December 12, 2011 Report Share Posted December 12, 2011 Hello to everybody! I am nearly finished with this one, only wondering whether it is better to include graphs that show grids or ones that do not. Does that makes any difference whatsoever? HEYYY! what program did u use to graph ur graphs? it would be very very useful if you cud tell me the software thanks download "Graph" heres the link for PCs http://download.cnet...4-10063417.html its an awesome and invaluble tool. just figet a bit with axis (double cleck on the tab on the left that says axis to edit them) OMG! thank you soooo much! i'm working on it now, and its way way better than geogebra (which i've been trying to work out for so long) I really appreciate it thanks a billion one question tho! how do i take a screen shot? i want to use it on my portfolio, so do i take a screenshot? or is there another method? Reply Link to post Share on other sites More sharing options...
diazn Posted December 13, 2011 Report Share Posted December 13, 2011 I am so lost on what to do with this project and it is due on Friday. Can someone give me the basic outlines of what to do so I can get started, I really do not want to get a bad grade!! Reply Link to post Share on other sites More sharing options...
fidelcastro Posted December 13, 2011 Report Share Posted December 13, 2011 (edited) Mine is due in on Wednesday and I am starting to go mad I have done an introduction, plotted the data into a graph & commented on the trends but I am really lost with picking functions which could model the behavior of the graph... I have been using the program 'Autograph' to plot the data points and then just used 'best fit' to find a curve that fits. But I have no Idea what to do with the equations I get There is a Linear one, a quadratic one, a cubic one, and a polynomial one... But I don't want to put them in if they are completely false and I have no Idea! I signed up to this website to find help but you guys are talking about these algebraic methods I haven't even heard of!! Please could someone slowly walk me through how I could proceed without doing it in tiny steps over hundreds of posts, sorry to (re-)bother you guys with this, but I have seriously gone through the entire thread and I still have no clue. I think it would also help others in the future if we do one genuine explanation! Thanks in advance Edited December 13, 2011 by fidelcastro 1 Reply Link to post Share on other sites More sharing options...
tank85 Posted December 14, 2011 Report Share Posted December 14, 2011 I have tried to "analytically" get a function for a cubic formula. The first time only like the first three point fit, so I tried to work it out with three other point. But I don't get a good model. I am using f(x)= ax3+bx2+cx+d Can someone spot a mistake in the function above? I also tried a exponential but also I am not getting a proper fit. Thanks for the help in advance. Reply Link to post Share on other sites More sharing options...
hanaar Posted December 15, 2011 Report Share Posted December 15, 2011 (edited) Do we have to show mathematically how we interpreted the parameters for the researcher's mode?Or can I say I just used my calculator to come up with?Can we use calculator or any technology to refine the analytical function?Or we should do that without technology? Edited December 16, 2011 by hanaar Reply Link to post Share on other sites More sharing options...
dessskris Posted December 16, 2011 Report Share Posted December 16, 2011 Did you find out how to fix the plummet??? I have the same problem (my equation works well for the first 8 points but then plummets down before the 9th point and 10th point, and i followed the guide precisely so I dont know what im doing wrong!!! If anyone could help me id be so grateful !!!!! s/he already posted how s/he solved the problem. when creating the matrix, choose the FIRST and LAST points, and some points in between. how do i graph a logistic function on geogebra i'd appreciate anyone who can get back asap!! thanks use your TI calculator, geogebra sucks does anyone know how to edit the axises on geogebra? as in so its not increasing from 0-10-20 or anything steadily on a scale but more like it jumps straight to 0 to 1950, 1955, 1960? I really need the y axis to be on the graph too, but if it increases on a scale, it definitly wont be in the screen shot. also, whats the best software for graphing for this assignment? geogebra seems so complicated ! would appreciate any reply ! use your TI, it's the best to use for this IA. and, use horizontal translation. so you edit the function. Reply Link to post Share on other sites More sharing options...
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