God Posted August 13, 2014 Report Share Posted August 13, 2014 i see similar questions come up quite often: The random variable X follows a poisson distribution. Given that P(X<=1) = 0.2, find the mean of the distribution. <= is less than or equal to. so i try to rearrange and i get to : e^-m (1+m) = 0.2 I dont know what to do next, anyone know ? Thanks! -GOD Reply Link to post Share on other sites More sharing options...
ctrls Posted August 13, 2014 Report Share Posted August 13, 2014 Is this a paper 2 question? There's sometimes questions which can't be solved algebraically, so you may have to use your GDC to find the answer that way. Unless I've missed something, wolframalpha suggests there is no algebraic solution to that equation. Reply Link to post Share on other sites More sharing options...
Negotiation Posted August 13, 2014 Report Share Posted August 13, 2014 Generally, you should just use the SOLVER option if you have it on the GDC. That can solve such equations for you. If the IB don't want you to do that, they'll let you know by asking for an exact answer, but generally they don't in Stats and Prob. Reply Link to post Share on other sites More sharing options...
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