STAT 200 Week 3 Homework Problems
4.1.4
A project conducted by the Australian Federal Office of Road Safety asked people many questions about
their cars. One question was the reason that a person chooses a given car,
...
STAT 200 Week 3 Homework Problems
4.1.4
A project conducted by the Australian Federal Office of Road Safety asked people many questions about
their cars. One question was the reason that a person chooses a given car, and that data is in table
#4.1.4 ("Car preferences," 2013).
Table #4.1.4: Reason for Choosing a Car
Safety Reliability Cost Performance Comfort Looks
84 62 46 34 47 27
Total=300
Safety
84
300
=.28 =28%
Reliability 62
300 =.21 =21%
Cost
46
300
=.15 =15%
Performance
34
300
=.11 =11%
Comfort
47
300 =.16 =16%
Looks 27
300
=.09 =.09%
Find the probability a person chooses a car for each of the given reasons.
4.2.2
Eyeglassomatic manufactures eyeglasses for different retailers. They test to see how many defective
lenses they made in a time period. Table #4.2.2 gives the defect and the number of defects.
Table #4.2.2: Number of Defective Lenses
Defect type Number of defects
Scratch 5865a
Right shaped – small 4613
Flaked 1992
Wrong axis 1838
Chamfer wrong 1596
Crazing, cracks 1546
Wrong shape 1485
Wrong PD 1398
Spots and bubbles 1371
Wrong height 1130
Right shape – big 1105
Lost in lab 976
Spots/bubble – intern 976
a.) Find the probability of picking a lens that is scratched or flaked.
(
5865
25981 )
+(
1992
25981 )−(
5865
25981 )
∗(
1992
25981 )=0.285
b.) Find the probability of picking a lens that is the wrong PD or was lost in lab.
(
1398
25981 )
+(
976
25981 )−(
1398
25981 )
∗(
976
25981 )=0.089
c.) Find the probability of picking a lens that is not scratched.
1−(
5865
25981 )=0.774
d.) Find the probability of picking a lens that is not the wrong shape.
1−(
1485
25981 )=0.943
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