what is ddref what is ddef? what is DDREF why is ddref not normally distributed what is dderef when ddref is normally distributed what is it what is ddef mean ddref is the ratio of two regression coefficients. how should i compare the two? what is dref which regression coefficient is normally distributed what is the dref in a meta-analysis which of these is the ratio of two regression coefficients is ddefer normally distributed what is ddref why is ddef variable variable not normally distributed ddrawf ratio what is the ddref in stats when do you combine two regression coefficients to make one estimate of the ddef? what is dderf mean for ddref what is ddef