Thread: binomial distribution, using cumulative distribution tables

The random variable X~B( 50, 0.40). Find

a) the largest value of k, such that
B)the smallest number r, such that P(X>r) <0.01

I have done part 'a', by simply looking at the tables, n=50, p=0.40 and looking for the value for X that gives a probability less than 0.05. Which is k=13.

But I am stuck on part 'b', because it asks for x>r, and the tables only give values for


Can someone show me how to work this out?

Thanks.

Originally Posted by Tweety

The random variable X~B( 50, 0.40). Find

a) the largest value of k, such that
B)the smallest number r, such that P(X>r) <0.01

I have done part 'a', by simply looking at the tables, n=50, p=0.40 and looking for the value for X that gives a probability less than 0.05. Which is k=13.

But I am stuck on part 'b', because it asks for x>r, and the tables only give values for


Can someone show me how to work this out?

Thanks.

Note that .

Originally Posted by awkward

Note that .

Thank you,

But wouldn't I have to work out the value of 'r' before I do this?

Originally Posted by Tweety

Thank you,

But wouldn't I have to work out the value of 'r' before I do this?

No.



if and only if



if and only if