TL;DR A sample table from the full results for data that look like this
Table 1: Coverage of 95% bca CIs. parameter n=5 n=10 n=20 n=40 n=80 means Control 81.4 87.6 92.2 93.0 93.6 b4GalT1-/- 81.3 90.2 90.8 93.0 93.8 difference in means diff 83.
Motivator: Novel metabolic role for BDNF in pancreatic β-cell insulin secretion
I’ll finish this some day…
knitr::opts_chunk$set(echo = TRUE, message=FALSE) library(tidyverse) library(data.table) library(mvtnorm) library(lmerTest) normal response niter <- 2000 n <- 9 treatment_levels <- c("cn", "high", "high_bdnf") insulin <- data.table(treatment = rep(treatment_levels, each=n)) X <- model.matrix(~ treatment, data=insulin) beta <- c(0,0,0) # no effects # the three responses are taken from the same cluster of cells and so have expected # correlation rho.
An answer to this tweet “Are there any #Rstats tidy expeRts who’d be interested in improving the efficiency of this code that gathers multiple variables from wide to long?
This works but it’s not pretty. There must be a prettier way…"
Wide data frame has three time points where participants answer two questions on two topics.
create data from original code #Simmed data Time1.Topic1.Question1 <- rnorm(500) data <- data.frame(Time1.Topic1.Question1) data$Time1.TOpic1.Question2 <- rnorm(500) data$Time1.
A skeletal response to a twitter question:
“ANOVA (time point x group) or ANCOVA (group with time point as a covariate) for intervention designs? Discuss.”
follow-up “Only 2 time points in this case (pre- and post-intervention), and would wanna basically answer the question of whether out of the 3 intervention groups, some improve on measure X more than others after the intervention”
Here I compare five methods using fake pre-post data, including
This is a skeletal post to work up an answer to a twitter question using Wright’s rules of path models. Using this figure
from Panel A of a figure from Hernan and Cole. The scribbled red path coefficients are added
the question is I want to know about A->Y but I measure A* and Y*. So in figure A, is the bias the backdoor path from A* to Y* through A and Y?
Setup Import Models as nested using “tank” nested within “room” as two random intercepts (using lme4 to create the combinations) A safer (lme4) way to create the combinations of “room” and “tank”: as two random intercepts using “tank2” Don’t do this This is a skeletal post to show the equivalency of different ways of thinking about “nested” factors in a mixed model. The data are measures of life history traits in lice that infect salmon.
Background Comparing marginal effects to main effect terms in an ANOVA table First, some fake data Comparison of marginal effects vs. “main” effects term of ANOVA table when data are balanced Comparison of marginal effects vs. “main” effects term of ANOVA table when data are unbalanced When to estimate marginal effects keywords: estimation, ANOVA, factorial, model simplification, conditional effects, marginal effects
Background I recently read a paper from a very good ecology journal that communicated the results of an ANOVA like that below (Table 1) using a statement similar to “The removal of crabs strongly decreased algae cover (\(F_{1,36} = 17.
