Command qchisq returns the value of chi square distribution for a certain value of probability.

qchisq(c(0.025), df=286, lower.tail=TRUE)

chisquared

For plotting the graph the command is:

local({
+ .x <- seq(213.788, 371.301, length.out=1000)
+ plotDistr(.x, dchisq(.x, df=286), cdf=FALSE, xlab=”x”, ylab=”Density”,
+ main=paste(“ChiSquared Distribution: Degrees of freedom=286”))
+ })

but can be done from Rcmdr