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Quick probability question

WalterWalter Registered User regular
edited July 2009 in Help / Advice Forum
I haven't had probability in years and a question is driving me crazy.

the probability of an event occurring is 5%
There are two trials
What is the probability of the even occurring during either of the two trials.

I know this is simple but I've been all over google and wikipedia. I would appreciate it if anyone could walk me through this. Thanks.

Walter on

Posts

  • FiggyFiggy Fighter of the night man Champion of the sunRegistered User regular
    edited July 2009
    Would it not be 5%?

    Figgy on
    XBL : Figment3 · SteamID : Figment
  • Last SonLast Son Registered User regular
    edited July 2009
    There would be a 90.25% of the event happening in neither trial(.95*.95), a 0.25% chance of the event happening in both trials(.05*.05), a 4.75% of it happening in trial A but not B(.95*.05) and a 4.75% chance of it happening in trial B but not A(.05*.95).

    Last Son on
  • HiroconHirocon Registered User regular
    edited July 2009
    If the trials are independent, and there is a 5% chance of the event occuring on each trial, then:

    The probability of the event NOT happening in either trial is (1-.05) *(1-.05) = .9025.

    The probability of the event happening in at least one of the two trials is 1-.9025 = .0975.

    Hirocon on
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