dessskris Posted November 17, 2011 Report Share Posted November 17, 2011 Hi all,I was wondering what difference it would make in the values of k,l and m in the logistic function if the x variable which is in years is set as follows:1950 is set as 0, 1955 set as 5 etc.?What would be the consequence?there is no consequence. if you make the years small integer values, you gotta do something to the polynomial you generate (hint: horizontal translation) so when you expand the brackets you'll get the same equation and when you plot it, it gives the data as in the table. Reply Link to post Share on other sites More sharing options...
caroline 4181 Posted November 20, 2011 Report Share Posted November 20, 2011 Hi everyone!I'm working with the coursework right now and i'm just wondering if there's some kind of wordlimit? I'm having trouble finding the balance between not being explicit enough and making it "overworked"...Read somewhere about a student getting 20/20 points and wrote like 40% more than his/her Extended Essay. Maybe I'm wrong but to me this seems kind of overworked.. Reply Link to post Share on other sites More sharing options...
dessskris Posted November 20, 2011 Report Share Posted November 20, 2011 Hi everyone!I'm working with the coursework right now and i'm just wondering if there's some kind of wordlimit? I'm having trouble finding the balance between not being explicit enough and making it "overworked"...Read somewhere about a student getting 20/20 points and wrote like 40% more than his/her Extended Essay. Maybe I'm wrong but to me this seems kind of overworked..there's no word limit, but I think you should write about 15-25 pages. that depends on how big your graphs and tables are, though. and font size, spacing etc Reply Link to post Share on other sites More sharing options...
DKMikey Posted November 21, 2011 Report Share Posted November 21, 2011 there's no word limit, but I think you should write about 15-25 pages. that depends on how big your graphs and tables are, though. and font size, spacing etcHow did you "revise" your model? I'm trying different things, but in the end I'm only getting worse off than what I first started with. Reply Link to post Share on other sites More sharing options...
dessskris Posted November 21, 2011 Report Share Posted November 21, 2011 lol you can try translation and stretch. or, just find a new function (start modelling everything all over) (you may choose to do it analytically or technologically) Reply Link to post Share on other sites More sharing options...
DKMikey Posted November 21, 2011 Report Share Posted November 21, 2011 (edited) lol you can try translation and stretch. or, just find a new function (start modelling everything all over) (you may choose to do it analytically or technologically) Basically, all I did was subtract like 0.0000004 from the g term. Not sure if that's substantial enough though. Edit: Also, according to our teacher trying a new function is bad, bad, bad. Edited November 21, 2011 by DKMikey Reply Link to post Share on other sites More sharing options...
dessskris Posted November 21, 2011 Report Share Posted November 21, 2011 lol you can try translation and stretch. or, just find a new function (start modelling everything all over) (you may choose to do it analytically or technologically) Basically, all I did was subtract like 0.0000004 from the g term. Not sure if that's substantial enough though. Edit: Also, according to our teacher trying a new function is bad, bad, bad. from the g term? what g? ahah yesss trying a new function is bad, but if one is desperate then that's better than nothing at all when is due? mind me replying a bit later (like 4 hours later)? Reply Link to post Share on other sites More sharing options...
robawalsh Posted November 22, 2011 Report Share Posted November 22, 2011 "Comment on how well this model fits the original data."What sorts of comments should I be making here? Is it adequate just to say which points/years don't fit the line and hence are discrepancies in the data? And that the model seems to fit the data closely, more closely than the other model...Is this enough? Reply Link to post Share on other sites More sharing options...
dessskris Posted November 23, 2011 Report Share Posted November 23, 2011 (edited) "Comment on how well this model fits the original data."What sorts of comments should I be making here? Is it adequate just to say which points/years don't fit the line and hence are discrepancies in the data? And that the model seems to fit the data closely, more closely than the other model...Is this enough?umm firstly say whether it fits and if so, how well (very well, well, quite well)then comment on the number of points that fit the model (like you said).and when you have gone to your second model, you can start comparing them.that's pretty much it. Edited November 23, 2011 by Desy Glau Reply Link to post Share on other sites More sharing options...
davver Posted November 27, 2011 Report Share Posted November 27, 2011 If any one needs help with this task, I finished it last term, so just ask Got 19/20 points on it, so thats AWESOME HELP ME! You kind of have to specify what you need help with...? If any one needs help with this task, I finished it last term, so just ask Got 19/20 points on it, so thats AWESOME I could use some help as well, what function did u use, i was thinking of using wither an exponential (so that the graph never goes below zero) or the cubic (cause if fits great with the points), but i have no friken idea how to find a,b,c,d (in a ax^3 + bx^2 + cx + d) or a,b (for ae^bx) analitically... any idea?? I used an exponential function... what you need to do is look for patterns in the data given. Like how much does the population increase for each 5 year period. Try that The increase in the population data doesn't grow exponentially though. the rate goes up and down each time. Reply Link to post Share on other sites More sharing options...
robawalsh Posted November 28, 2011 Report Share Posted November 28, 2011 I'm doing my Maths SL IA Type II - Population trends in China.A logistic function will never reach it's upper bound, it will be an asymptote, continuing to infinity.But does it start at zero? Or does the bottom half of the sigmoid curve continue to infinity too?Thanks Reply Link to post Share on other sites More sharing options...
dessskris Posted November 29, 2011 Report Share Posted November 29, 2011 I'm doing my Maths SL IA Type II - Population trends in China.A logistic function will never reach it's upper bound, it will be an asymptote, continuing to infinity.But does it start at zero? Or does the bottom half of the sigmoid curve continue to infinity too?Thanksyou mean at the origin? go figure. substitute x=0 and if you get y=0 then yes it starts from the origin. Reply Link to post Share on other sites More sharing options...
Manev93 Posted December 6, 2011 Report Share Posted December 6, 2011 I'm desperate I just received the task today and is due for next wednesday I'm trying not to procrastinate but i have no idea how to approach or even begin the investigation! HELP ASAP Reply Link to post Share on other sites More sharing options...
Sabs44 Posted December 6, 2011 Report Share Posted December 6, 2011 I'm desperate I just received the task today and is due for next wednesday I'm trying not to procrastinate but i have no idea how to approach or even begin the investigation! HELP ASAPYou've gotta be more specific about what you want help with... the introduction? Or the first plotting of the data? 1 Reply Link to post Share on other sites More sharing options...
Manev93 Posted December 6, 2011 Report Share Posted December 6, 2011 I'm desperate I just received the task today and is due for next wednesday I'm trying not to procrastinate but i have no idea how to approach or even begin the investigation! HELP ASAPYou've gotta be more specific about what you want help with... the introduction? Or the first plotting of the data?I have not started so yes basically the introduction and the first plotting data and the rest.. Reply Link to post Share on other sites More sharing options...
Sabs44 Posted December 6, 2011 Report Share Posted December 6, 2011 I'm desperate I just received the task today and is due for next wednesday I'm trying not to procrastinate but i have no idea how to approach or even begin the investigation! HELP ASAPYou've gotta be more specific about what you want help with... the introduction? Or the first plotting of the data?I have not started so yes basically the introduction and the first plotting data and the rest.."Define all relevant variables and parameters clearly." This is the first thing to do. I'm not sure if it's discussed earlier in this thread... but basically you define your two variables, and define the parameters on them. (For example, population can't really be negative.)"Use technology to plot the data points from the above table on a graph." For this, use Excel or GeoGebra, whichever you prefer. Just use the data they've given you to make the points. Good luck! Reply Link to post Share on other sites More sharing options...
Timmy_Timmy Posted December 7, 2011 Report Share Posted December 7, 2011 Hi, Im having trouble typing in the researcher's model in excel (i've already figured it out). Can someone please help me with this? Reply Link to post Share on other sites More sharing options...
Sabs44 Posted December 7, 2011 Report Share Posted December 7, 2011 Hi, Im having trouble typing in the researcher's model in excel (i've already figured it out). Can someone please help me with this?I don't think you can... try using GeoGebra, it worked great for me! Reply Link to post Share on other sites More sharing options...
Guest Animistic Anaemia Posted December 8, 2011 Report Share Posted December 8, 2011 I'm desperate I just received the task today and is due for next wednesday I'm trying not to procrastinate but i have no idea how to approach or even begin the investigation! HELP ASAP You've gotta be more specific about what you want help with... the introduction? Or the first plotting of the data? I have not started so yes basically the introduction and the first plotting data and the rest.. Try to identify all the limiting factors that may affect a population growth. If you take either Biology or ESS, you'll know that there are some key stuff that limit growth. I can't tell you exactly what it is because I can't give you the answers And for your model, try using a cubic model Be sure to analyse all its positive and negative things because it will be important in the end when you'll have to choose which model you want to modify Hi, Im having trouble typing in the researcher's model in excel (i've already figured it out). Can someone please help me with this? Use Graph, it's the best plotting software I know for Windows. However, if you have a Mac, use the incorporated Grapher which is even better than graph Reply Link to post Share on other sites More sharing options...
dessskris Posted December 8, 2011 Report Share Posted December 8, 2011 actually, use your TI calculator. excel is ****ty for type 2 tasks. I use TI-Nspire, got a very nice interface, beautiful graphs and all so you may have a different view, but features-wise, TI is the best to use. it can generate the researcher's model and plot it with the data. too perfect. Reply Link to post Share on other sites More sharing options...
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