Question

Find the probabilities associated with the standard normal random variable z
P(z>5)

Answer 1

The probability is going to be very close to 0 (essentially could be considered 0 in practice) I don't think most standard normal tables show values beyond z=4, and so for z>4, you have less than a 0.0001 probabiliy, so expect even a lower probability for z>5

Answer 2

thats what i assumed , but what would i write for my answer?

Answer 3

I think writing \(\approx 0\) should be sufficient. My standard normal table shows values for \(P(Z \le z)\) for z at 3.99 as the highest value. and there it shows 1.0000, meaning that \(P(Z > 3.99)\), to 4 digits, would be 0.0000 ... so ya .. 0 should be good enough

Answer 4

unless you have a calculator that can spit out the exact value.. which would be super small anyway

Answer 5

i do, but how would i enter the data in the calculator?

Answer 6

hmm I am not sure .. I never had a fancy calculator.. just a basic scientific one. Um, you can enter this on WolframAlpha though: http://www.wolframalpha.com/input/?i=P%28Z%3E5%29%2C+Z~N%280%2C1%29

Answer 7

i dont understand how to enter it though ):

Answer 8

on Wolfram? or on the calculator

Answer 9

either /= we havent used calculators for this

Answer 10

Wolfram shows you the value on the site. I already put the input. The value is the number that popped up.. \(2.88 \times 10^{-7}\)

For your calculator, I am not sure...

But if you only used tables to do find the probabilities, then ya just approximately 0 should be more than sufficient!

Answer 11

oh! alright! thank you :)

Answer 12

=]