[R] FW: Nested and/or crossed and 2 level random factor

2013-07-11 Thread Linda Bürgi
Dear All, I have two quick questions about my study design. For 4 years, once every season, we destructively sampled larvae on bushes (the same bushes every time) and measured parasitism on these larvae. We had 10 bushes per location and two locations. We are interested in whether parasiti

Re: [R] LD50 and SE in GLMM (lmer)

2010-01-12 Thread Linda Bürgi
d, and do not have a reference handy > to check to be sure, so perhaps you can find a local statistician to > help? I myself always have a preference to use the logit / logistic > over probit, as they are both symmetric around 0.5 and are often > reported to provide similar results. > >

[R] LD50 and SE in GLMM (lmer)

2010-01-07 Thread Linda Bürgi
Hi All! I am desperately needing some help figuring out how to calculate LD50 with a GLMM (probit link) or, more importantly, the standard error of the LD50. I conducted a cold temperature experiment and am trying to assess after how long 50% of the insects had died (I had 3 different i