**A**nother occurrence [out of many!] of a question on X validated where the originator (*primitivus petitor*) was trying to get an explanation without the proper background. On either Bayesian statistics or simulation. The introductory sentence to the question was about “trying to understand how the choice of priors affects a Bayesian model estimated using MCMC” but the bulk of the question was in fact failing to understand an R code for a random-walk Metropolis-Hastings algorithm for a simple regression model provided in a introductory blog by Florian Hartig. And even more precisely about confusing the R code *dnorm(b, sd = 5, log = T)* in the prior with *rnorm(1,mean=b, sd = 5, log = T)* in the proposal…

*“You should definitely invest some time in learning the bases of Bayesian statistics and MCMC methods from textbooks or on-line courses.” X*

So I started my answer with the above warning. Which sums up my feelings about many of those X validated questions, namely that *primitivi petitores* lack the most basic background to consider such questions. Obviously, I should not have bothered with an answer, but it was late at night after a long day, a good meal at the pub in Kenilworth, and a broken toe still bothering me. So I got this reply from the *primitivus petitor* that it was a patronizing piece of advice and he prefers to learn from R code than from textbooks and on-line courses, having “looked through a number of textbooks”. Good luck with this endeavour then!

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