[Rd] historical significance of Pr(>Chisq) < 2.2e-16

[Michael Friendly]

Where does the value 2.2e-16 come from in p-values for chisq tests such 
as those
reported below?

 > Anova(cm.mod2)
Analysis of Deviance Table (Type II tests)

Response: Freq
LR Chisq Df Pr(>Chisq)
B 11026.2 1 < 2.2e-16 ***
W 7037.5 1 < 2.2e-16 ***
Age 886.6 8 < 2.2e-16 ***
B:W 3025.2 1 < 2.2e-16 ***
B:Age 1130.4 8 < 2.2e-16 ***
W:Age 332.9 8 < 2.2e-16 ***
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
 >

-- 
Michael Friendly     Email: friendly AT yorku DOT ca
Professor, Psychology Dept. & Chair, Quantitative Methods
York University      Voice: 416 736-2100 x66249 Fax: 416 736-5814
4700 Keele Street    Web:   http://www.datavis.ca
Toronto, ONT  M3J 1P3 CANADA