[R] Bonferroni p-value greater than 1

[Horace Tso]

Hi folks,

I use the outlier.test in package car to test a lm model and the bonferroni p value returned is shown as NA. When the object is typed it indicates the p value is greater than 1. I'm not sure how to interpret it. 

Thanks in advance.

Horace W. Tso


> outlier.test(mod)$test
max|rstudent|            df  unadjusted p  Bonferroni p 
   2.04106376   18.00000000    0.05618628            NA 

> outlier.test(mod)

max|rstudent| = 2.041064, degrees of freedom = 18,
unadjusted p = 0.05618628, Bonferroni p > 1

Observation: 1 

The lm model looks fine to me,

> summary(mod)

Call:
lm(formula = x ~ ind, na.action = na.fail)

Residuals:
    Min      1Q  Median      3Q     Max 
-1.2082 -0.5200  0.1309  0.5725  0.9593 

Coefficients:
            Estimate Std. Error t value Pr(>|t|)    
(Intercept) 59.84586    0.31900   187.6  < 2e-16 ***
ind         -0.16768    0.02541    -6.6 2.57e-06 ***
---
Signif. codes:  0 '***' 0.001 '**' 0.01 '*' 0.05 '.' 0.1 ' ' 1 

Residual standard error: 0.705 on 19 degrees of freedom
Multiple R-Squared: 0.6963,     Adjusted R-squared: 0.6803 
F-statistic: 43.56 on 1 and 19 DF,  p-value: 2.57