FIT OF THE SNAKE DATA BY GLS 
WITH POWER VARIANCE, THETA KNOWN AND EQUAL TO 0.8 
 
 
OLS estimate  667.0326 391.4139 1.009001 1.594886 
 
Estimate of assumed constant SD of y  27.87661 
 
 
GLS estimate of beta  683.5062 412.8713 0.996444 1.479212 
 
GLS estimate of beta  682.9178 411.8084 0.997041 1.482353 
 
GLS estimate of beta  682.9223 411.8201 0.997041 1.48229 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
GLS estimate of beta  682.9218 411.8193 0.997042 1.482292 
 
Final estimate of sigma  0.267756 
 

Formula: ywt ~ weightfunc(x, b1, b2, b30, b31, delta, wt)

Parameters:
     Estimate Std. Error t value Pr(>|t|)    
b1  682.92182   25.10195   27.21  < 2e-16 ***
b2  411.81929   30.79892   13.37 6.02e-16 ***
b30   0.99704    0.02978   33.48  < 2e-16 ***
b31   1.48229    0.04832   30.68  < 2e-16 ***
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1 

Residual standard error: 0.2678 on 38 degrees of freedom

Number of iterations to convergence: 6 
Achieved convergence tolerance: 1.578e-06