A study of 479 children determined the lighting with which they slept as infants
ID: 3305508 • Letter: A
Question
A study of 479 children determined the lighting with which they slept as infants and their incidence of myopia (near-sightedness) later in childhood. Slept With No Myopia Myopia Total 155 15 172 Darkness 153 72 232 Nightlight 34 36 75 Full light Total- a) What's the probability of a child having slept in darkness and experiencing no myopia? 342 123 14 479 b) What's the probability of a child having slept in darkness or experiencing no myopia? What's the probability of a child experiencing no myopia given that they slept in darkness? c) Of the children who slept with full light, what's the probability of them experiencing no myopia? d) e) Is the light a child slept with independent of their incidence of myopia? Explain.Explanation / Answer
Answer to the question below:
a. P( darkness and no myopia) = 155/479 = .324
b. P(darkness or no myopia) = (172+342-155)/479 = .75
c. P( no mypoia given they slept in darkness) = 155/172 = .9011
d. P( out of childern who slept in full light expericed no myopia) = 34/75 = .4533
e. As there is more lighting the incidence ratio of myopia increases. For example, it the least for Darkness, more more nighlight ( low form of light), and highest for Full light (brightest).
Hence, light a child slept with is not independent of their incidence of myopia
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