find th smallest value of n in a binomial distribution for which we can assert:
P{ |(Xn/n) – p| < .1} ≥ .9
Well this translates into: find the smallestsuch that:
where the rvthe number of successes in
independent trials with probability of success in a single trial of
. Now given the title of this thread I assume we are supposed to use a normal approximation to the binomial to do this, in which case we have:
.
of the probabilty mass of a normal RV is contained within
standard deviations of the mean, so if
we have:
which will allow you to find the smallestfor which this is true.
Now you can do the case whereyourself.
CB