The R Book

Significance Stars

If these worry you, then turn them off. Significance stars are shown by default next to the p values in the output of statistical models.

gg<-read.table("c:\\temp\\Gain.txt",header=T)
attach(gg)
names(gg)

[1] "Weight" "Sex" "Age" "Genotype" "Score"

This is what the default output looks like for an analysis of covariance:

model<-lm(Weight~Age+Sex)
summary(model)
Coefficients:
                  Estimate   Std. Error   t value  Pr( | t |)
(Intercept)        8.17156      0.33118    24.674     < 2e–16     ***
Age                0.29958      0.09185     3.262     0.00187     **
Sexmale           −0.83161      0.25980    −3.201     0.00224     **
- - -

Signif. codes:   0 '***'  0.001 '**' 0.01 '*' 0.05 '.' 0.1''1

Residual standard error: 1.006 on 57 degrees of freedom
Multiple R–Squared: 0.2681, Adjusted R–squared: 0.2425
F–statistic: 10.44 on 2 and 57 DF, p–value: 0.0001368

Here is the output with the significance stars turned off:

options(show.signif.stars=FALSE)
summary(model)

Coefficients:
                Estimate     Std. Error t value     Pr(> | t |)
(Intercept)     8.17156     0.33118     24.674          < 2e–16
Age             0.29958     0.09185      3.262          0.00187
Sexmale        −0.83161     0.25980     −3.201          0.00224

Residual standard error: 1.006 on 57 degrees of freedom
Multiple R–Squared: 0.2681, Adjusted R–squared: 0.2425
F–statistic: 10.44 on 2 and 57 DF, p–value: 0.0001368

You decide.