LPP

Age: 33

Aug
30
comment finding and replacing a string within a line with an if statement
I sometimes want to replace only the second instance. For example, this is a usual few lines of the text file 'Cg200 <abxcd> {10} ; 34 USC_1320-496-0 <hkxhk> {01} ; 51' In line 1, the change should be ab to ba only because of the {01},while in line 2 the change should be hk to kh for the second instance only.
Aug
30
asked finding and replacing a string within a line with an if statement
Apr
17
comment Testing for a significant difference between ML estimates: Likelihood ratio or Wald test?
Any ideas on how to code the LRT in R?
Apr
17
comment Testing for a significant difference between ML estimates: Likelihood ratio or Wald test?
@Ernest : I have not gotten that before...I think my llhood equations must be set up wrong when I incorporate both data sets and estimate 4 parameters....
Apr
17
awarded Supporter
Apr
17
awarded Editor
Apr
17
revised Testing for a significant difference between ML estimates: Likelihood ratio or Wald test?
added 1666 characters in body
Apr
17
comment Testing for a significant difference between ML estimates: Likelihood ratio or Wald test?
@Ernest ok. In the setup you just described, is L1 the reduced or constrained model (where s1=s2?) -- I tried to setup a new likelihood where s is the same for both sets of data and i sum the likelihoods Lnull(s1=s2,d,data1, data2) and then he unrestricted L2(s1,s2,d,data1 data2) where I estimate each s seperately and sum the resultant likelihoods. But the unrestricted likelihood, L2, returns "needs finite values of fn".
Apr
17
comment Testing for a significant difference between ML estimates: Likelihood ratio or Wald test?
@guest OK. Any suggestion how to code that to a single call to optim()? I have two different sets of genotype data (one for each environment) that Id have to work in. I also have two unknowns, s and d. so I have to do this for s1=s2 and d1=d2.
Apr
16
asked Testing for a significant difference between ML estimates: Likelihood ratio or Wald test?
Apr
16
comment further hypothesis testing for the difference in ML estimates after optim in R
@ernest Ok. I dont really know the sampling distribution of s. It is being estimated from genotype data under a simple fitness model seperately in two environments. I was hoping that I could use the estimated variance from the hessian and the point estimate to do some simple post-hoc hypothesis testing of whether the estimate of s in one environment is statistically different from the s in the other environment (does selection change across environments). Is a wald test appropriate? If I could simply estimate a difference parameter, I could test it against zero...
Apr
16
awarded Student
Apr
16
awarded Student
Apr
15
awarded Editor
Apr
15
asked further hypothesis testing for the difference in ML estimates after optim in R