# Thread: Teenage Pregnancy Probability

1. ## Teenage Pregnancy Probability

Help will be more appreciated......
A recent study on teenage pregnancy indicates that 5% of the female population will get pregnant sometime in their teenage years. Suppose 15 teenage women were randomly selected. Find the probability that 1 of these women will get pregnant during their teenage years.

2. Hello Allenge
Originally Posted by Allenge
Help will be more appreciated......
A recent study on teenage pregnancy indicates that 5% of the female population will get pregnant sometime in their teenage years. Suppose 15 teenage women were randomly selected. Find the probability that 1 of these women will get pregnant during their teenage years.
This is an example of a Binomial Distribution. The probability of 'success' (that a given teenage woman chosen at random would get pregnant in their teenage years), is denoted by $\displaystyle p$. The probability of 'failure' (that she would not), is denoted by $\displaystyle q = 1-p$. If the experiment (choosing and interviewing a teenage woman at random) is repeated $\displaystyle n$ times, then the probability of $\displaystyle r$ successes and $\displaystyle (n-r)$ failures is:

$\displaystyle \binom{n}{r}p^rq^{n-r}$

So you need to put $\displaystyle p = 0.05, q= 0.95, n = 15, r = 1$.

(I think the answer is 0.366 (3 d.p.)