2
$\begingroup$

With a perfect use of the condom you have a 2% chance to get pregnant each year. These figures seem surprisingly high to me. So I was wondering what the chance is to have a baby after a lifelong use (let's assume 25-35 years).

What if you use the pill? And with both the pill & condom? What with the "typical use" scenario?

Pregnancy chances after one year of use:

  • Pill | Perfect use: 0.3%
  • Pill | Normal use: 8%
  • Condom | Perfect use: 2%
  • Condom | Normal use: 15%
  • 0
    There is only one way, and it is written right below.2011-03-07

1 Answers 1

5

If you have a probability of failure for one year of $p$, you have a probability of no failure for one year of $1-p$. Then the chance of no failure for $n$ years is $(1-p)^n$ if you assume the chances are independent.

  • 0
    Tha$n$ks for the help. Looks l$i$ke a safe bet with a 0.2% chance after 30 years.2011-03-07