1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Statistics Standard Deviation Problem

  1. Sep 23, 2010 #1
    1. The problem statement, all variables and given/known data
    A jet engine manufacturer estimates that the chance of a “critical-item” failure within a jet engine’s afterburner module is approximately 1 in 220. What is the standard deviation of the number of launches, before a “critical-item” failure occurs within a jet engine’s afterburner module?

    2. Relevant equations

    I would guess that you would use the standard deviation equation, but im not really understanding what to use when they give you "1 in 120"
    Please Help?
  2. jcsd
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Can you offer guidance or do you also need help?
Draft saved Draft deleted