[Gretl-users] Error message in MLE script

Hi! I've been trying to write an MLE script for a Probit model where the dependent value can take 3 values, but when I run the script, I get an "Data types not conformable for operation". What does that mean and how do I fix it? mle loglik3 = (yy=1)ln(cnorm(c1-xb2)) + (yy=2)ln(cnorm(c2-xb2) - cnorm(c1-xb2)) + (yy=3)ln(1 - cnorm(c2-xb2)) scalar c1 = -10 scalar c2 = -10 scalar pb1 = -10 scalar pb2 = -10 series xb2 = pb1*x1 + pb2*x2 params pb1 pb2 c1 c2 end mle gretl version 1.8.4 Current session: 2010-02-25 16:24 ? mle loglik3 = (yy=1)ln(cnorm(c1-xb2)) + (yy=2)ln(cnorm(c2-xb2) - \ cnorm(c1-xb2)) + (yy=3)ln(1 - cnorm(c2-xb2)) ? scalar c1 = -10 ? scalar c2 = -10 ? scalar pb1 = -10 ? scalar pb2 = -10 ? series xb2 = pb1*x1 + pb2*x2 ? params pb1 pb2 c1 c2 ? end mle Data types not conformable for operation Error executing script: halting