A gist for the source code: https://gist.github.com/lwaldron/54b60f0c71b8100d24d89fa1ef38c44a

Raw data

Coefficients

##              Estimate Std. Error  t value    Pr(>|t|)
## (Intercept) 3.0000909  1.1247468 2.667348 0.025734051
## x1          0.5000909  0.1179055 4.241455 0.002169629
##             Estimate Std. Error  t value    Pr(>|t|)
## (Intercept) 3.000909  1.1253024 2.666758 0.025758941
## x2          0.500000  0.1179637 4.238590 0.002178816
##              Estimate Std. Error  t value    Pr(>|t|)
## (Intercept) 3.0024545  1.1244812 2.670080 0.025619109
## x3          0.4997273  0.1178777 4.239372 0.002176305
##              Estimate Std. Error  t value    Pr(>|t|)
## (Intercept) 3.0017273  1.1239211 2.670763 0.025590425
## x4          0.4999091  0.1178189 4.243028 0.002164602

Residuals vs Fitted

Normal Q-Q

## Warning: not plotting observations with leverage one:
##   8

Scale-Location

## Warning: not plotting observations with leverage one:
##   8

Residuals vs Leverage