t test of coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 2199.89917 177.83217 12.371 4.312e-13 *** Time -1.10622 0.08994 -12.300 4.966e-13 *** --- Signif. codes: 0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 > model_gls <- gls(St.Effort ~ Time, data = tuna2, correlation = corAR1(form = ~ 1 | Time)) > summary(model_gls) Generalized least squares fit by REML Model: St.Effort ~ Time Data: tuna2 AIC BIC logLik 171.44 176.9091 -81.71998 Correlation Structure: AR(1) Formula: ~1 | Time Parameter estimate(s): Phi 0 Coefficients: Value Std.Error t-value p-value (Intercept) 2199.8992 132.33720 16.62344 0 Time -1.1062 0.06701 -16.50936 0 Correlation: (Intr) Time -1 Standardized residuals: Min Q1 Med Q3 Max -1.4018943 -0.7567719 -0.2352387 0.5232677 2.1560236 Residual standard error: 3.336846 Degrees of freedom: 31 total; 29 residual4