Incorrect intercept in Bayesian linear regression
Dear Jasp team
I came across a potential issue in JASP's Bayesian linear regression output. For various datasets I consistently found an unlikely and inconsistent intercept. The inconsistency can be easily verified as for any (multiple) linear regression model (y=c+mi.xi) with intercept c and slope coefficients mi (i=1, ...), the intercept can be easily derived from: c=<y>-mi.<xi>.
However, the intercept c that is returned by JASP turns out to be exactly equal to <y>. This cannot be correct, as it only holds for the rare case that mi.<xi>=0. So, I suspect a bug. Possibly a wrong variable value is sent to the user interface. The other coefficients seem quite OK.
I've noticed some other posts about the intercept, but so far I couldn't find any answers, e.g. see