```r
cor.test(sqrt(stdres(mod.negbin)),predict(mod.negbin))
```

```
## Warning in sqrt(stdres(mod.negbin)): NaNs produced
```

```
## 
## 	Pearson's product-moment correlation
## 
## data:  sqrt(stdres(mod.negbin)) and predict(mod.negbin)
## t = 4.8093, df = 7, p-value = 0.001945
## alternative hypothesis: true correlation is not equal to 0
## 95 percent confidence interval:
##  0.5071470 0.9737071
## sample estimates:
##       cor 
## 0.8761687
```

```r
cor.test(sqrt(stdres(mod)),predict(mod))
```

```
## Warning in sqrt(stdres(mod)): NaNs produced
```

```
## 
## 	Pearson's product-moment correlation
## 
## data:  sqrt(stdres(mod)) and predict(mod)
## t = -0.50019, df = 2, p-value = 0.6666
## alternative hypothesis: true correlation is not equal to 0
## 95 percent confidence interval:
##  -0.9803574  0.9236405
## sample estimates:
##        cor 
## -0.3334484
```