[R] Shading area under PDF of t -distribution

[Dimitris Rizopoulos]

try this:

curve(dt(x, 74), from = -4, to = 4)
x <- seq(-1.96, 1.96, len = 100)
y <- dt(x, 74)
polygon(c(x[1], x, x[100]), c(dt(-4, 74), y, dt(4, 74)),
     col = "red", border = NA)


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
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      http://www.student.kuleuven.be/~m0390867/dimitris.htm


Quoting Chung-hong Chan <chainsawtiney at gmail.com>:

> Dear R experts,
>
> I have plot the PDF of t distribution with df = 74.
> curve(dt(x,df=74),from=-4, to=4)
>
> how can I shade the area under curve (for example, col="red") from   
> t=+- 1.996?
>
> Thank you.
> Regards,
> CH
>
> --
> CH Chan
> Research Assistant - KWH
> http://www.macgrass.com
>
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