On 10/13/07, hany <[EMAIL PROTECTED]> wrote: > What I want is just like Figure 1: Histogram and the Normal > Distribution for PCC Compressive Strength Data in > http://training.ce.washington.edu/WSDOT/Modules/08_specifications_qa/normal_distribution.htm > (I don't know how I can post picture here.) I have a series data and > want to get a bell curve from this data with perl.
So, first you want to analyze the data and determine the bell curve which is the best fit. Then, you want to draw a graph (i.e., you want your program to output an image file) to show the bell curve superimposed over the data. Is that correct? I should double-check that an image is your ultimate goal here. That is, do you really need it? For example, if your need is to determine whether the bell curve fits the data "well enough", you don't need an image for that; there are statistical techniques that can measure the fit of the curve. You can draw a bar chart (for example) with off-the-shelf modules on CPAN. But to draw a curve over a bar chart, I'd probably do that in a separate pass. (Of course, I'd check that there isn't a module that already does this. But I don't know of one offhand.) If a separate pass doesn't work so well, I might try modifying or subclassing the code in the module, or I might scrap it and write code to draw the whole thing from scratch. > I searched in http://search.cpan.org/ before I posted here. But I > can't find the example. Jeff's suggestion can create splined > (smoothed) line graphs. I think this isn't a bell curve. Am I right? > Can you both give me more advice and example? Well, yes and no. We're here to help beginners with Perl, and you sound like you qualify. But we're not here to teach statistical analysis techniques, even if the program touches upon them; we try to keep this list mostly on-topic. (It's more accurate that way. If I give you bad advice about Perl, the Perl experts here can put us both back on the right track. But if I give you bad advice about statistics, the statistics experts are busy elsewhere, reading their own lists. You'll get better answers by directing your questions separately to the right groups.) In particular, I haven't seen a program that does what (I think) you need, but I'm pretty sure I could put one together in a few hours with a few modules from CPAN. It may take you more than a few hours, even after you understand the underlying statistical mathematics; but it should be do-able. I recommend that you first get the help you need (if any) on what statistical stuff you want to do. Next, search CPAN to select some modules that can help you. Finally, when you have trouble writing the Perl code to do a specific step, we're here to help you with that. Good luck with it! --Tom Phoenix Stonehenge Perl Training -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED] http://learn.perl.org/
