Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: Statistic maths

  1. Jul 16, 2010 #1
    Please try this question and see whether you got my answer...i am having some doubt

    The random variable X is normally distributed with mean V and variance C^2. It is known that P(x>102)=0.42 and P(x<97)=0.25

    calculate V(mean) and variance c^2

    i got mean 100.8 and variance(-5.7)^2
  2. jcsd
  3. Jul 16, 2010 #2


    User Avatar
    Homework Helper

    You need to show some work, but one comment: if you say the variance is [itex] (-5.7)^2 [/itex], you are implicitly saying the standard deviation is [itex] -5.7 [/itex], which is impossible.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook