Bayes Theorem Problem As part of general prenatal care in the US, pregnant women are routinely screened for the presence of a variety of genetic conditions in their unborn children using a method called Non-Invasive Prenatal Testing or NIPT. This method uses a blood test to gather the baby’s placental DNA that is present in the mother’s blood.
One condition that is routinely tested for in this way is Down Syndrome, which affects approximately 417 in every 100000 children. This test has been found to be 99.3% accurate in correctly detecting Down Syndrome and has a very low false positive rate of only 94 out of 100000 tests. (Source)

If a mother receives a positive result for Down Syndrome through NIPT, what is the probability that her child does not have Down Syndrome? Give your answer correctly rounded to three significant figures.