In mrzdcmps/changeofevidence: Change of Evidence

knitr::opts_chunk$set(echo = TRUE)

Generate Sample Data

set.seed(9878)

exp=rbinom(100,20,0.52)
con=rbinom(100,20,0.5)

summary(exp)
summary(con)

df <- data.frame(condition = c(rep("exp", 100), rep("con", 100)),
                      value = c(exp, con))

Load library

library(changeofevidence)

Bayes Factor testing

Calculate Sequential Bayes Factors

# Undirectional one-sample t-tests with broad prior
bf.exp <- bfttest(exp, mu = 10, alternative = "two.sided", prior.loc = 0, prior.r = 0.707)
print(bf.exp)

# Use exact=FALSE for a quicker test that doers not calculate every single BF
bf.con <- bfttest(con, mu = 10, alternative = "two.sided", prior.loc = 0, prior.r = 0.707, exact=FALSE)
print(bf.con)

# only the last 5 data points
bfttest(con, mu = 10, alternative = "two.sided", prior.loc = 0, prior.r = 0.707, nstart = length(con)-5)

# Directional paired samples t-test with narrow prior
bf.paired <- bfttest(exp, con, alternative = "greater", prior.loc = 0, prior.r = 0.1)
print(bf.paired)

# Independent samples t-test with informed prior
bf.between <- bfttest(value ~ condition, data = df, alternative = "less", prior.loc = 0.1, prior.r = 0.1)
print(bf.between)

Plot Seq BFs

# Plot seqbf object
plot(bf.paired)

# Plot multiple BFs
plotbf(list(exp=bf.exp$BF, con=bf.con$BF))

Robustness analyis

bf.paired.robust <- bfRobustness(bf.paired)
print(bf.paired.robust)
plot(bf.paired.robust)

Simulations

Create simulations

# Indicate the amount of trials of one experimental run (e.g. 100 subjects * 20 trials)
# Specify the same test parameters as the test(s) you want to compare to (in this case the one-sample t-tests.)
sims <- simcreate(100*20, n.sims = 100, mean.scores = 10, use.files = F, alternative = "two.sided", prior.loc = 0, prior.r = 0.707)

Plot BFs with simulation data

plot(bf.paired, sims.df = sims)
plotbf(list(exp=bf.exp$BF, con=bf.con$BF), sims.df = sims)

Change of evidence measures

CoE 1: Maximum BF

r.exp.maxbf <- maxbf(bf.exp, sims.df = sims)
r.con.maxbf <- maxbf(bf.con, sims.df = sims)

CoE 2: BF Energy

r.exp.nrg <- energybf(bf.exp, sims.df = sims)
r.con.nrg <- energybf(bf.con, sims.df = sims)

Coe 3: FFT Amplitude Sum

# Create Fast Fourier Transforms of Sequential BFs
fft.exp <- fftcreate(bf.exp)
fft.con <- fftcreate(bf.con)

# Compare amplitude sums with simulations
r.exp.fft <- ffttest(fft.exp, sims.df = sims)
r.con.fft <- ffttest(fft.con, sims.df = sims)

# Plot FFTs
# Use parameter "coordy" to ensure a comparable coordinate system
plotfft(fft.exp, sims.df = sims)
plotfft(fft.con, sims.df = sims)

mrzdcmps/changeofevidence documentation built on Feb. 27, 2025, 3:10 a.m.