probability help

[kriptik]

hey people, i was stuck on how to do this question , anyone that can help

[TrueTears]

Argh not this question lol, you need to use binomial and also then create a table in your calculator (I only know how to do it for Ti-89) and then find the value of X which corresponds to the first probability that exceeds 0.99. Quite tedious...

[sajib_mostofa]

ahh yes that dreadful question...

[stonecold]

Here is how to do it on a TI Nspire:

http://vcenotes.com/forum/index.php/topic,27287.msg293219.html#msg293219

[kriptik]

how bout with the casio classpad?

[stonecold]

Classpad can't do it.

It can't even solve algebraic equations with factorials in it.

Best chance you have is to screw around with a table or spreadsheet and you might be able to get it.

[fady_22]

The easiest way to do it is using trial and error. I find that (especially with the TI-89), it takes way too long to solve.
For this question, use binomcdf(n,.7,50,n). Change the value for n until you JUST get over .99. You will find that this occurs at n=86.

[vea]

The easiest way to do it is using trial and error. I find that (especially with the TI-89), it takes way too long to solve.
For this question, use binomcdf(n,.7,50,n). Change the value for n until you JUST get over .99. You will find that this occurs at n=86.

Why is n the no. of trials AND the upper limit?
I thought the upper limit is meant to be infinity here or am I doing something wrong?

Are we finding n for Pr(X>50)=0.99 here?

Thanks in advance.

EDIT: Nvm
Just remembered that for a binomial distribution if there are 86 trials then Pr(X>50) is the values from 50-86.