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From |
Lance Wiggains <[email protected]> |

To |
[email protected] |

Subject |
Re: st: RE: using loop to generate distributions with different means and standard deviations |

Date |
Sat, 21 May 2011 17:38:56 -0400 |

I was able to piece the code together. It is true that when generating multiple drawnorms in a loop the means and standard deviations have to be specified in matrix form. This is the code that I found to work. forvalues i=1/3 { mkmat mean_item_`i' if `i'==_n, matrix(m) mkmat sd_item_`i' if `i'==_n, matrix(sd) drawnorm product`i'_dist, m(m) sd(sd) } Thanks for all of your help. Lance On Fri, May 20, 2011 at 11:47 PM, Lance Wiggains <[email protected]> wrote: > I tried the command you suggested > > ds mean* sd* > forvalues i=1/3 { > drawnorm product`i'_dist, m(mean_item_`i') sd(sd_item_`i') > } > > but it failed, I got this error > > means(mean_item_1) invalid > r(198); > > end of do-file > > r(198); > > I think the variable might need to be in matrix form. Does that sound > right? If so, do you know how would I create the vector with the > relevant information. > > Thanks for all of your help, > > Lance > > On Fri, May 20, 2011 at 2:44 PM, Sarah Edgington <[email protected]> wrote: >> Lance, >> Is your actual data really different from the simulated data you've shown? >> If not I don't understand why the solution I suggested before doesn't solve >> your problem. If your variables are actually numbered like you've shown, >> it's still just a -forvalues- loop to get the drawnorm part working. >> >> forv i=1/3 { >> drawnorm product`i', m(max_product`i') sd(sd_product`i') >> } >> >> Unless you give more specific information about the actual problem you're >> trying to solve and why the suggested solution doesn't work, I don't think >> you're going to get much help. >> >> -Sarah >> >> >> >> -----Original Message----- >> From: [email protected] >> [mailto:[email protected]] On Behalf Of Lance Wiggains >> Sent: Friday, May 20, 2011 11:29 AM >> To: [email protected] >> Subject: st: using loop to generate distributions with different means and >> standard deviations >> >> Sorry for the vagueness. Right now I'm just using simulated data for 3 >> different products. Here is my code: >> My data looks like this >> Week Product 1 Product 2 Product 3 >> 1 50 45 50 >> 2 60 50 40 >> 3 70 55 30 >> 4 80 50 20 >> 5 90 45 10 >> 6 100 50 0 >> >> tsset week >> gen n=_n >> egen max_n=max(n) >> >> ds week n max_n, not >> foreach var in `r(varlist)'{ >> tssmooth ma ms_`var'= `var', weights(1 1<2>1) >> } >> >> ds ms* >> foreach var in `r(varlist)' { >> gen week3_`var'=`var' if n==max_n >> egen max_week3_`var'=max(week3_`var') >> drop week3* >> >> } >> drop ms* >> >> ds week n max_*, not >> foreach var in `r(varlist)' { >> gen max_`var'=max_week3_ms_`var' >> } >> drop max_week* >> >> keep if n+3>=max_n >> ds week n max*, not >> foreach var in `r(varlist)'{ >> egen sd_`var'=sd(`var') >> } >> >> rename max_n maximum_n >> >> ds max_* sd* week, not >> foreach var in `r(varlist)'{ >> drop `var' >> } >> >> drawnorm product1, m(max_product1) sd(sd_product1) >> >> Thanks, >> >> Lance >> - Hide quoted text - >> >> On Wed, May 18, 2011 at 1:51 PM, Sarah Edgington <[email protected]> wrote: >>> Lance, >>> That's a different problem. From your original post I assumed you had >>> all the variables already created. >>> One strategy for writing loops is to write out the code for the first >>> two examples of something repetitive you want to do. Then identify >>> the parts of the example that remain the same across the examples. >>> If you post the code your trying to repeat we may be able to help you >>> but your current description is too vague for me to do much more than >>> offer vague suggestions of how to think about loops. >>> -Sarah >>> >>> -----Original Message----- >>> From: [email protected] >>> [mailto:[email protected]] On Behalf Of Lance >>> Wiggains >>> Sent: Wednesday, May 18, 2011 10:36 AM >>> To: [email protected] >>> Subject: Re: st: RE: using loop to generate distributions with >>> different means and standard deviations >>> >>> I've tried that but the problem is that I'm pre-calculating the means >>> and sd's for the variable because I'm only using the last 3-4 >>> observations for each variable to calculate those values. I'm doing >>> this because I want it to reflect the changes that happen recently. My >>> mean function uses tssmooth, with weights (1 1<2>), to average the >>> last 3 weeks of sales. So if sales were 70,80,90, and 100 I get a >>> value of 92.5 for my mean. It also calculates a SD for the last 3-4 >>> observations. Then I want to plug those numbers into the drawnorm function >> using a loop. Any idea about how that would work? >>> >>> Lance >>> >>> On Wed, May 18, 2011 at 1:16 PM, Sarah Edgington <[email protected]> wrote: >>>> Lance, >>>> Try something like this: >>>> >>>> forv i=1/3 { >>>> drawnorm name`i', m(mean_var`i') sd(sd_var`i') >>>> } >>>> >>>> You'll run into problems, though, if your data actually includes the >>>> variable names you list since there isn't a sd_var1. >>>> >>>> -Sarah >>>> >>>> -----Original Message----- >>>> From: [email protected] >>>> [mailto:[email protected]] On Behalf Of Lance >>>> Wiggains >>>> Sent: Wednesday, May 18, 2011 10:09 AM >>>> To: [email protected] >>>> Subject: st: using loop to generate distributions with different >>>> means and standard deviations >>>> >>>> Statalist members, >>>> >>>> I'm trying to get Stata to generate a distribution of data from >>>> variables in my data set. >>>> >>>> My appended data looks like this >>>> mean_var1=90 >>>> standard_deviation_var1=5 >>>> mean_var2=100 >>>> sd_var2=10 >>>> mean var3=110 >>>> sd_var3=15 >>>> and so on >>>> >>>> I'm need a loop that will take my variables and create the >>>> distributions for me. >>>> I've been using the drawnorm command >>>> drawnorm name1, m(mean_var1) sd(sd_var1) but I can't get it to >>>> recognize more than 1 variable at a time >>>> >>>> I want it to perform the distribution command for each pair of my >>> variables. >>>> I.e. (m_var1, sd_var1), (m_var2, sd_var2) , (m_var3, sd_var3) >>>> >>>> Thanks for your consideration, >>>> >>>> Lance >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/statalist/faq >> * http://www.ats.ucla.edu/stat/stata/ >> >> * >> * For searches and help try: >> * http://www.stata.com/help.cgi?search >> * http://www.stata.com/support/statalist/faq >> * http://www.ats.ucla.edu/stat/stata/ >> > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

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**References**:**st: using loop to generate distributions with different means and standard deviations***From:*Lance Wiggains <[email protected]>

**st: RE: using loop to generate distributions with different means and standard deviations***From:*"Sarah Edgington" <[email protected]>

**Re: st: RE: using loop to generate distributions with different means and standard deviations***From:*Lance Wiggains <[email protected]>

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