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2.1
(a)
Category
A
B
C
Frequency
13
28
9
(b)
The Bar Chart
A
Percentage
26%
56
18
26%
B
56%
C
18%
0%
10%
20%
(c)
30%
40%
Percentage of Category
50%
The Pie Chart
C
18%
A
26%
B
56%
d)
The Pareto Chart
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
0%
B
A
C
60%
2.15
(a)
(b)
(c)
(d)
2.19
(a)
(b)
Ordered array: 9.1 9.4 9.7 10.0 10.2 10.2 10.3 10.8 11.1 11.2
11.5 11.5 11.6 11.6 11.7 11.7 11.7 12.2 12.2 12.3
12.4 12.8 12.9 13.0 13.2
The stem-and-leaf display conveys more information than the ordered array. We can
more readily determine the arrangement of the data from the stem-and-leaf display
than we can from the ordered array. We can also obtain a sense of the distribution of
the data from the stem-and-leaf display.
The more likely gasoline purchase is between 11 and 11.9 gallons.
Yes, the third row is the most frequently occurring stem in the display and it is located in
the center of the distribution between 11 and 11.9 gallons.
Ordered array: 35, 85, 110, 120, 170, 180, 240, 260, 300, 380, 380, 460
Stem-and-Leaf Display
for Life
Stem unit:
100
0
1
2
3
4
(c)
(d)
The stem-and-leaf display conveys more information than the ordered array. We can
more readily determine the arrangement of the data from the stem-and-leaf display
than we can from the ordered array. We can also obtain a sense of the distribution of
the data from the stem-and-leaf display.
The battery life clusters around the high 100s and high 300s.
(a)
Strength
1500 -- 1549
1550 -- 1599
1600 -- 1649
1650 -- 1699
1700 -- 1749
1750 -- 1799
1800 -- 1849
1850 -- 1899
Frequency
1
2
2
7
5
7
3
3
Percentage
3.33%
6.67%
6.67%
23.33%
16.67%
23.33%
10.00%
10.00%
Histogram
8
Frequency
2.25
49
1278
46
088
6
6
4
2
0
1525 1575 1625 1675 1725 1775 1825 1875
Midpoints
(b)
Percentage Polygon
25%
20%
15%
10%
5%
1925
1875
1825
1775
1725
1675
1625
1575
1525
1475
0%
Cumulative Percentage Polygon
100%
90%
80%
70%
60%
50%
40%
30%
20%
10%
(d)
1949
1899
1849
1799
1749
1699
1649
1599
1549
1499
1449
0%
The strength of all the insulators meets the company’s requirement of at least 1500.
CHAPTER 3
3.1
(a)
(b)
Mean = 6
Median = 7
There is no mode.
Range = 7
Variance = 8.5 Interquartile range = 5.5
Standard deviation = 2.9
Coefficient of variation = (2.915/6)•100% = 48.6%
Z scores: 0.343, -0.686, 1.029, 0.686, -1.372
None of the Z scores is larger than 3.0 or smaller than -3.0. There is no outlier.
Since the mean is less than the median, the distribution is left-skewed.
(c)
(d)
3.3
(a)
(b)
Mean = 6
Median = 7
Mode = 7
Range = 12
Variance = 16 Interquartile range = 6 Standard deviation = 4
Coefficient of variation = (4/6)•100% = 66.67%
Z scores: 1.5, 0.25, -0.5, 0.75, -1.5, 0.25, -0.75. There is no outlier.
Since the mean is less than the median, the distribution is left-skewed.
(c)
(d)
3.7
(a), (b)
Price
Mean
Median
Mode
Standard Deviation
Sample Variance
Range
Minimum
Maximum
Sum
Count
First Quartile
Third Quartile
Interquartile Range
Coefficient of Variation
(c)
(d)
3.13
36.5333
35.6000
#N/A
4.3896
19.2687
12.0000
31.0000
43.0000
219.2000
6
33.7500
40.2500
6.5000
12.0154%
Since the mean is only slightly greater than the median, the data are slightly rightskewed.
There is a $12 difference between the most expensive and the least expensive outlet.
The prices vary around $36.53 with half of the outlets being more expensive than
$35.6. The middle half of the prices fall between $33.75 and $40.25.
(a) Excel output:
Mean
Median
Mode
Standard Deviation
Sample Variance
Range
Minimum
Money Market
4.442
4.4
4.38
0.07823
0.00612
0.17
4.38
One-Year CD
4.878
4.85
4.85
0.040866
0.00167
0.09
4.85
Maximum
Sum
Count
First Quartile
Third Quartile
Interquartile Range
Coefficient Variable
3.21
4.55
22.21
5
4.38
4.525
0.145
1.7612%
(b)
Money market accounts have more variation in the highest yields offered than oneyear CDs because they have the larger variance, range, interquartile range and
coefficient of variations.
(a)
(b)
Population Mean = 6
 2 = 9.4
  3.1
51
3.23
4.94
24.39
5
4.85
4.92
0.07
0.8378%
(a)

X
i 1
N
i
N

514
 10.28
50
2 
 X
i 1
i
 
N
2

204.92
 4.0984
50
   2 = 2.0245
3.31
(b)
(c)
64%
94%
100%
These percentages are lower than the empirical rule would suggest.
(a)
min = 4, 1st quartile = 16, median = 23.5, 3rd quartile = 30, max = 56.
Box-and-whisker Plot
Fat
0
10
20
(b)
The amount of fat is right-skewed.
30
40
50
60