A survey classified a large number of adults according to whether they were judg

Question

A survey classified a large number of adults according to whether they were judged to need eyeglasses to correct their reading vision and whether they used eyeglasses when reading. The proportions falling into the four categories are shown in the table. (Note that a small proportion, 0.02, of adults used eyeglasses when in fact they were judged not to need them.) Used Eyeglasses for Reading Judged to Need Eyeglasses

If a single adult is selected from this large group, find the probability of each event.

(a) The adult is judged to need eyeglasses.

(b) The adult needs eyeglasses for reading but does not use them.

(c) The adult uses eyeglasses for reading whether he or she needs them or not.

Explanation / Answer

If a single adult is selected from the large group.

a) The probability of judged to need eyeglasses for YES is 0.42 , 0.13

So P(needs eyeglasses) = 0.42 + 0.13 = 0.55

b) We have to find the probability that the adult needs eyeglasses for reading but does not use them.

The probability judged to need eyeglasses YES but Used Eyeglasses for reading NO is 0.13

So P(Needs eyeglasses for reading but does not use them) = 0.13

c) P( Uses eyeglasses ) = 0.42 + 0.02 = 0.44

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.