Probability Question

  1. Drakkith

    Staff: Mentor

    An event has an 8% chance to occur per try. How would I calculate the chance of the event occurring at least once after 3 tries?
     
  2. jcsd
  3. jbriggs444

    jbriggs444 1,936
    Science Advisor

    Is the probability in one trial independent of the actual results in the others?

    If so, can you write a formula for the event to not occur at all in three tries?
     
  4. PeroK

    PeroK 1,478
    Homework Helper
    Gold Member

    The chance of it not occurring in 3 tries is $$0.92^3$$
    So, you want $$1- 0.92^3$$
     
    1 person likes this.
  5. jtbell

    Staff: Mentor

    To gain some insight into this problem, try the following brute-force method. List all the possible outcomes for the set of three tries:

    1=no, 2=no, 3=no : probability = 0.92 * 0.92 * 0.92 = …
    1=yes, 2=no, 3=no : probability = 0.08 * 0.92 * 0.92 = …
    etc.

    Enumerate all the outcomes (how many of them are there?), calculate the probability for each one, and add up the ones that meet your criterion.
     
    1 person likes this.
  6. Drakkith

    Staff: Mentor

    Awesome. Thanks guys.
     
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