search for: fieller

Folks I have modified an existing function to calculate 'ec/ld/lc' 50 values and their associated Fieller's confidence limits. It is based on EC50.calc (writtien by John Bailer) - but also borrows from the dose.p (MASS) function. My goal was to make the original EC50.calc function flexible with respect to 1) probability at which to calculate the expected dose, and 2) the link function. I wo...

...and hope I'm not wasting your time. For a class I'm teaching in archaeological data analysis, I'm trying to put together a routine that calculates the so-called Petersen index and, especially, confidence intervals for the index. This was introduced to archaeologists by N.R.J. Fieller and A. Turner in an article in Journal of Archaeological Science (1982) called Number Estimation in Vertebrate Samples. They say that "calculation of precise confidence intervals for population sizes is, in principle at least, straightforward. It involves calculation of cumulative...

Classification: UNCLASSIFIED Caveats: NONE A similar question has been posted in the past but never answered. My question is this: for probit analysis, how do you program a 95% confidence interval for the LD50 (or LC50, ec50, etc.), including a heterogeneity factor as written about in "Probit Analysis" by Finney(1971)? The heterogeneity factor comes into play through the chi-squared

...l. The form of the data with arbitrary n and not assuming equal variance: m1 = mean of (control group) n = 7 m2 = mean of (control group w/ treatment) n= 10 m3 = mean of (test group) n = 8 m4 = mean of (test group w/ treatment) n = 9 H0: m2/m1 = m4/m3 restated, H0: m2/m1 - m4/m3 = 0; Method 1: Fieller's Intervals Use fieller's theorum available in R as part of the mratios package. This is a promising way to compute standard error/confidence intervals for each of the two ratios but will not yield p-values for significance testing. Significance by non-overlap of confidence intervals is t...

thanks a lot Renaud. but i was interested in Finney's fiducial confidence intervals of LD50 so to obtain comparable results with SPSS. But your reply leads me to the next question: does anybody know what is the best method (asymptotic, bootstrap etc.) for calculating confidence intervals of LD50? i could "get rid" of Finney's fiducial confidence intervals but

Hello all, This is something that I am sure has a really suave solution in R, but I can't quite figure out the best (or even a basic) way to do it. I have a simple linear regression that is fit with lm for which I would like to estimate the x intercept with some measure of error around it (confidence interval). In biology, there is the concept of a developmental zero - a temperature under

...n how to properly call this (Ista Zahn) 99. Re: R2WinBUGS help (bmiddle) 100. Re: how do remove those predictor which have p value greater than 0.05 in GLM? (shubha) 101. Re: Help: Standard errors arima (Dennis Murphy) 102. Probit Analysis: Confidence Interval for the LD50 using Fieller's and Heterogeneity (UNCLASSIFIED) (Kenney, Colleen T CTR USA AMC) 103. how to calculate derivative (Yogesh Tiwari) 104. Re: cpgram: access data, confidence bands (David Scott) 105. Re: Probit Analysis: Confidence Interval for the LD50 using Fieller's and Heterogeneity (UN...