Find the probability that a child under 16 is myopic.
Researchers at the university of pennsylvania school of medicin have determined that children under 2 years old who sleep wth the lights on have a 36% chance of becomin myopic before they are 16. Children who sleep in darkness have a 21% probability of becoming myopic. A survey indicates hat 28% of children under 2 sleep with some light on.
So, 28% have lights on, and of those, 36% turn myopic.
On the other side, 72% have lights off, and of those, 21% turn myopic.
0.28*0.36 = 0.1008 lights-on myopic.
0.72*0.21 = 0.1512 lights-off myopic.
Together, 0.2520 will myopic, 0.748 will not be.
Answer: 25.2% (should be rounded to 25%)