Yap Posted May 9, 2013 Report Share Posted May 9, 2013 Hi!I just checked an old Math Studies test and there they tell me, at the first question, to find the Standard Deviation... However, the question is only worth one point which for some reason got me to think if the effort I would have put into it really would have been worth it, and I thought, perhaps there is a quicker way to gain Standard Deviation than I know of? Because the way I do it is tedious.That's why I ask you, is there a quick way of finding a Standard Deviation? Reply Link to post Share on other sites More sharing options...
adhamhussein Posted May 9, 2013 Report Share Posted May 9, 2013 using ur GDC.Create a list (L1) and (L2). L1 is the list and L2 is the frequency.Press STAT, CALC, 1-Var Stats, Fill in L1,L2 (in the old version) or it will give u prompt telling u the options, the Standard Deviation is the alpha sign it looks like an a next to it an x (ax) 1 Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) Ah, Thanks!Edit: but it doesn't seem to work. I'm doing the exam from Nov 2011 question 1bii.... And the answer is incorrect when doign so... I might be doing something wrong but myL1 L225 3055 4665 2275 1285 895 2My Answer becomesStandard Deviation is 24.83 or 22.67 depending on which one of them you were looking at... The alpha one was 22.7... But answer says 19.2 Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
maereth Posted May 9, 2013 Report Share Posted May 9, 2013 I entered those numbers and I have standard deviation 19.2 ;p maybe you just made a mistake somewhere in the lists.. 1 Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) I have checked multiple times over and over again and it's the same...Lets See if Im doing this right...First I click Stat, Enter to Edit the L1 and L2In the way aboveThen I click Stat again, go to CALC, click 1 var StatisticsEdit: Perhaps it is my calculator checking L2 and L3 or something? But I dont have anything in L3 or so only L1 and L2.. Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
maereth Posted May 9, 2013 Report Share Posted May 9, 2013 that's weird. what are the other values, like mean for example? Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) Mean becomes 66.666666666667n=6 Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
maereth Posted May 9, 2013 Report Share Posted May 9, 2013 I have totally different values.. It's hard to help over the internet when I don't see your calculator, maybe you could ask a friend or teacher tommorow. Besides, don't you get a school calculator for the exam, that can be working properly ;d Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 Uh... Yeah. .. But I tried with a second TI-84 Plus and I get the same value of both of them.... So It's probably me who are doing something wrong and not the calculator Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) Ashashdha!I think I god it! I will write this for any future students who might be in the same place as meThe Idea was not to write it like this:L1 L225 3055 4665 2275 1285 895 2But to only use L1And simply write the frequency inside it, likeL125252525252525252525252525(Continue with this untill you got thirty 25)Then, you continue with writing fourtysix 55s5555555555etc..etc.Switch to 65s, where it was 22 65s, then you write 22 65s65656565656565Then when you are done, use 1 Var Statisticsetc... Hope this is correct! Never got to learn this method in class oOI will also like to thank Maereth and Adhamhusein(lol) for trying to help me! Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
lilianna009 Posted May 9, 2013 Report Share Posted May 9, 2013 You should change Calc-Set-1 Var Freq-List 2 1 Reply Link to post Share on other sites More sharing options...
maereth Posted May 9, 2013 Report Share Posted May 9, 2013 Well, the idea of using frequency list (L2) is for writing one value only once, not 25 times ;p But if this works for you, maybe it's safer that you did this on your exam ;d Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) Yeah... That seems to be the only option for me as the other one doesn't seem to work... but Idk.... I will check with my classmates tomorrow morning if they know anything...@Lilianna, what do you mean ?Also, it should be degree, right? (Not Radians) Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
alefal Posted May 9, 2013 Report Share Posted May 9, 2013 (edited) Note that I am assuming you're using a CASIO GDC. In the maths studies course, we only use degrees. Make sure it says 'Deg' besides 'Angle' in the setup (accessible by pressing SHIFT+MENU). What Lilianna was trying to say, is that you should make sure you have set up the VAR correctly. Go to the STAT part of your calculator, press CALC (should be F2). In the lower right corner, you should see 'SET.' Press F6 to access SET. Here you see some lines that refer to how the 1VAR and 2VAR is calculated. We are apparently concentrating on 1VAR for your task. 1VAR XList should always be set to 'List1'. 1VAR Freq is either on '1' or a list, most usual is the List2. If it does not say 'List2' now, press down and make sure you have marked that line. Then, press F2. Press the number of the list in which you have written the frequency in the STAT main page (I'd be surprised if this is not List2), and press the number for that list now (for instance, for 'List2', press '2').Press Exe twice. Press '1VAR' (F1) and check the standard deviation now. Good luck!EDIT: I just checked, and I get 19.2 as st.dev.. Edited May 9, 2013 by alefal 1 Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) Hi!Thank you for your detailed description, but I'm using a TI-84 >_>Anyone with a TI-84 minding to show how to do it? Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
alefal Posted May 9, 2013 Report Share Posted May 9, 2013 Is this to any help? http://www.stat.osu.edu/~stated/resources/calc_how_to/TI-84/84_mean_sd_discrete_rv.pdf Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 (edited) Is this to any help? http://www.stat.osu.edu/~stated/resources/calc_how_to/TI-84/84_mean_sd_discrete_rv.pdfWas pretty much what maereth said :/Just so you know... I get the same result from 1 - Var - Stat and 2 - Var - Stat.... Don't know if that is any of help in tracking the problem. Edited May 9, 2013 by Yap Reply Link to post Share on other sites More sharing options...
maereth Posted May 9, 2013 Report Share Posted May 9, 2013 (edited) You know I once had a problem with one equation-solving program, it kept giving the wrong result, and my teacher didn't know why this happened so she just told me to use a different app. If using only one list works then go for it, unless you figure out what Lilianna meant, because unfortunately I don't know ;dI'm saying this because I think you should focus on other aspects of maths too and not let this distract you tommorow, maybe you won't even need to calculate sd ;p Edited May 9, 2013 by maereth Reply Link to post Share on other sites More sharing options...
Yap Posted May 9, 2013 Author Report Share Posted May 9, 2013 Yeah! Thank you all guys for being so helpful! I'm really grateful.It seems for me that I will use only one list as it appears to be working unlike two lists.... It may cost me 1-2 minutes extra typing in all those numbers, but perhaps those minutes will be worth it! We shall see!I wish you all good luck tomorrow for Exams! It's soon over!Thanks! 1 Reply Link to post Share on other sites More sharing options...
alefal Posted May 9, 2013 Report Share Posted May 9, 2013 Is this to any help? http://www.stat.osu.edu/~stated/resources/calc_how_to/TI-84/84_mean_sd_discrete_rv.pdfWas pretty much what maereth said :/Just so you know... I get the same result from 1 - Var - Stat and 2 - Var - Stat.... Don't know if that is any of help in tracking the problem.Okay, sorry about that! But that means that Lilianna pointed at the right thing, which I described, though for the wrong calculator. There should be a settings page somewhere, where you can alter how 1VAR reads the lists. Unfortunately, I can't find anything about it on the net.Anyways, good luck tomorrow! Reply Link to post Share on other sites More sharing options...
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