Hello, I would be pleased if you could help me in determining the standard error of the estimate for ?place2L1.N2? from the following table: Call: glm(formula = y ~ places2 + shellheight, family = quasibinomial) Deviance Residuals: Min 1Q Median 3Q Max -3.41415 -0.70817 0.01214 0.79700 3.18387 Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) -1.60286 0.22383 -7.161 8.92e-12 *** places2L1.N2 0.31922 0.08095 3.944 0.000104 *** shellheight 0.08742 0.01135 7.703 3.12e-13 *** --- Signif. codes: 0 ?***? 0.001 ?**? 0.01 ?*? 0.05 ?.? 0.1 ? ? 1 (Dispersion parameter for quasibinomial family taken to be 1.354491) Null deviance: 441.61 on 252 degrees of freedom Residual deviance: 355.52 on 250 degrees of freedom AIC: NA Number of Fisher Scoring iterations: 3 I know that the mean value is -1.60286+0.31922 and that the Std. Error (0.08095) should be the standard error for the difference between ?(Intercept)? and ?places2L1.N2? (i.e. 0.31922). But when I take this Std. Error as Sqrt((sA2/nA)+(sB2/nB)) With sqrt(sA2/nA) being the Std. Error for the intercept (i.e. 0.22383), then sqrt (sB2/nB)) should be the Std. Error for places2L1.N2. But this calculation isn?t right. I don?t get the right Std. Error for the (Intercept) and therefore also not for places2L1.N2. What?s wrong in this calculation? Thank you for your help, Alexander. _______________________________________________________________________ DSL zum Nulltarif + 20 Euro Extrapr?mie bei Online-Bestellung ?ber die DSL Freundschaftswerbung! http://dsl.web.de/?ac=OM.AD.AD008K15279B7069a