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, 0.01, of adults used eyeglasses when in fact they were judged not to need them.)

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.

Used Eyeglasses
for Reading Judged to Need
Eyeglasses Yes No Yes 0.45 0.15 No 0.01 0.39

Explanation / Answer

from above"

a)

P(adult is judged to need eyeglasses)=0.45+0.15=0.60

b){ adult needs eyeglasses for reading but does not use them)=0.15

c)

P(adult uses eyeglasses for reading whether he or she needs them or not)=0.45+0.01=0.46

used eyeglasses need eyeglasses Yes no total Yes 0.45 0.15 0.6 No 0.01 0.39 0.4 total 0.46 0.54 1

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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