search for: delta_

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2011 Jan 03
1
Greetings. I have a question with mixed beta regression model in nlme.
...Gamma_{1i} = c_1 + v_{1i} * *The vector* *(u_{0i}, u_{1i})'* *has normal distribution with mean* *(0, 0)'* *and covariance matrix* *sigma_{00} sigma_{01} sigma_{10} sigma_{11} * *The vector* *(v_{0i}, v_{1i})'* *has normal distribution with mean* *(0, 0)'* *and covariance matrix* *delta_{00} delta_{01} delta_{10} delta_{11} * *The* *w_{ij}s are independents. Each* *w_{ij}* *has mean* *0* *and variance * *W*. *The unknown parameters are:* * b_0, b_1, b_2, c_0, c_1, c_2, sigma_{00}, sigma_{10}, sigma_{11}, delta_{00}, delta_{10}, **and* *delta_{11}*. *The question is: How can I use...
2011 Jan 03
0
Greetings. I have a question with mixed beta regression model in nlme (corrected version).
...Gamma_{1i} = c_1 + v_{1i} * *The vector* *(u_{0i}, u_{1i})'* *has normal distribution with mean* *(0, 0)'* *and covariance matrix* *sigma_{00} sigma_{01} sigma_{10} sigma_{11} * *The vector* *(v_{0i}, v_{1i})'* *has normal distribution with mean* *(0, 0)'* *and covariance matrix* *delta_{00} delta_{01} delta_{10} delta_{11} * *The* *w_{ij}s are independents. Each* *w_{ij}* *has mean* *0* *and variance * *W*. *The unknown parameters are:* * b_0, b_1, b_2, c_0, c_1, c_2, sigma_{00}, sigma_{10}, sigma_{11}, delta_{00}, delta_{10}, **delta_{11}** **and* *W*. *The question is: How can...
2010 Oct 04
0
spatial interaction (gravity) model as Poisson regression
...ve searched the archives extensively, and there are several mentions of this question, but I have yet to find anything concrete that I can wrap my head around... apologies if I have missed something. Basically, the conventional origin constrained model would look something like this: T_{ij} = exp(\delta_{i} + \log{A_{j}} - \beta D_{ij}) ~ \varepsilon_{ij} where \delta_{i} is a constant parameter speci?c to the ith zone, A_{j} is the attractiveness of the jth location, and D_{ij} is the distance between i and j. Note that \varepsilon_{ij} is just the multiplicative error term of the ?ow from i to j,...
2008 Jan 31
3
Log rank test power calculations
Does anyone have any ideas how I could do a power calculation for a log rank test. I would like to know what the suggested sample sizes would be to pick a difference when the control to active are in a ratio of 80% to 20%. Thanks Dan -- ************************************************************** Daniel Brewer, Ph.D. Institute of Cancer Research Email: daniel.brewer at icr.ac.uk