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Announcement
• Sept. 17th follows Monday Schedule
• No AMS102 Lecture on September 17th
• Quiz will be given on Thursday
Pareto Diagram
70
60
50
fingernail
biting
frequency
40
30
20
10
0
TV
paper
Phone
Driving Shopping
Other
Pareto’s Law
• Any collection of events consists of only a
few that are major in that they are the ones
that occur most of the time
Discrete (Quantitative) Data
• Daily Computer
Stoppages:
131101011022000121
200164331240
Value
0
1
2
3
4
5
Freq
9
10
5
3
2
0
Rel. Freq.
6
Total
1
30
.033
1.000
.300
.333
.167
.100
.067
.000
Line Diagram
0.35
0.3
0.25
0.2
0.15
0.1
0.05
0
0
2
4
6
x
Continuous Variable
• Dot Diagram
• Histogram
• Stem-and-Leaf Display
Dot Diagram
• Number of Days of the
first six heart
transplant patients at
Stanford 15 3 46 623
126 64
0
200
400
Small Set of Numbers
600
800
Homework
• 2.10 2.20 2.22 2.24
Histogram
• 40 Cash Register Receipts
16.00 58.50 68.20 78.00 79.45 142.20
145.35 186.70 209.05 216.75 219.70 247.55
249.10 256.00 257.00 262.35 268.60 269.60
270.15 284.45 319.00 332.00 343.20 350.75
354.90 372.60 383.40 389.20 404.55 420.20
428.50 432.40 44.60 446.40 456.80 458.10
493.95 511.95 521.05 621.35
Histogram
Class Intervals
Frequency
Relative Freq
0-125
5
.125
125-250
8
.200
250-375
13
.325
375-500
11
.275
500-625
3
.075
Total
40
1.000
Histogram
Histogram
• The Total Area of a histogram is one
• Area of each bar represents the relative
frequency
• Height = Relative Freq / Width of Interval
• When all intervals have the same width, the
height can be frequency
• Class intervals are not unique, choose one
that gives best view of the feature
• Check the example in the course website.
Stem-and-Leaf Display
• Exam Scores of 50
Students
75 98 42 75 84 87 65
59 63 86 78 37 99 66
90 79 80 89 68 57 95
55 79 88 76 60 77 49
92 83 71 78 53 81 77
58 93 85 70 62 80 74
69 90 62 84 64 73 48
72
37
4 289
5 35789
6 022345689
7 01234556778899
8 00134456789
9 0023589
Stem-and-Leaf Display
• Doesn’t lose any information
• Appropriate for Small to Moderate Size
Data set
• Leafs can be two digits some time
• Too many stems are not desirable