Estimating the variability of a population by one sample?

Tony zeng <xh.along <at> gmail.com> writes:

       I am meetting one problem.I am estimating  the variability of a
population using one sample.I must do two-side and one-side hypothesis
test,and estimate the confidence interval,But I don't know which
function I can use !

You should describe your problem a bit more clearly, best by giving a sample
set, and how the result should look like. With a bit of guesswork, the 
following might come close to what you want :

t.test(rnorm(100,0.21))

rnorm() generates the test vector, put your data there instead.

Dieter