update_prior {truelies} | R Documentation |
Calculate posterior distribution of the proportion of liars
Description
update_prior
uses the equation for the posterior:
\phi(\lambda | R; N,P) = Pr(R|\lambda; N,P) \phi(\lambda) /
\int Pr(R | \lambda'; N,P) \phi(\lambda') d \lambda'
where \phi
is the prior and Pr(R | \lambda; N, P)
is the
probability of R reports of heads given that people lie with probability
\lambda
:
Pr(R | \lambda; N, P) = binom(N, (1-P) + \lambda P)
Usage
update_prior(heads, N, P, prior = stats::dunif, npoints = 1000)
Arguments
heads |
Number of good outcomes reported |
N |
Total number in sample |
P |
Probability of bad outcome |
prior |
Prior over lambda. A function which takes a vector of values between 0 and 1, and returns the probability density. The default is the uniform distribution. |
npoints |
How many points to integrate on? |
Value
The probability density of the posterior distribution, as a one-argument function.
Examples
posterior <- update_prior(heads = 30, N = 50, P = 0.5, prior = stats::dunif)
plot(posterior)
[Package truelies version 0.2.0 Index]