Probability of seeing i but not j in k multinomial trials

37 Views Asked by At

If we have a multinomial distribution $p_1,\ldots,p_n$ and we perform $k$ trials. What is the probability that we see (at least) an outcome $i$ but none of the outcomes is $j$?

1

There are 1 best solutions below

1
On BEST ANSWER

This is the probability that none of the outcomes is $j$ minus the probability that none of the outcomes is either $i$ or $j$:

$$ \left(1-p_j\right)^k-\left(1-p_i-p_j\right)^k\;. $$