Thread: Binomial Distribution

Hiya guys, thanks in advance

There are 15children in a class
1)what is the probability that i)0 ii)1 iii)2 iiii) at least 3 were born in january.

Thank you

Let be the probability of a child who were born in January; be the probability of a child who were NOT born in January.

It is easy to see that and

According to the Binomial Distribution:

Here we have , for (i), (ii) and (iii), you can let , and respectively.
Note for (iv), you can find the probability by

Roy