Chapter 2
Methods for
Describing Sets of
Data
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2.1
Describing Qualitative Data
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Definition
2- 3
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Definition
2- 4
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Definition
2- 5
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Table 2.1
2- 6
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Definition
2- 7
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Figure 2.1 SPSS summary table for types of
aphasia
2- 8
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Figure 2.2 SAS bar graph for type of
aphasia
2- 9
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Figure 2.3 MINITAB pie chart for type of
aphasia
2 - 10
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Figure 2.4 SPSS Pareto diagram for type of
aphasia
2 - 11
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Definition
2 - 12
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Figure 2.5 SAS summary tables for DRUG
and COMP
2 - 13
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Figure 2.6 MINITAB side-by-side bar graphs
for COMP by value of DRUG
2 - 14
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Figure 2.7 SPSS summary tables for COMP
by value of drug
2 - 15
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Figure SIA2.1a MINITAB pie charts for
Gender, Disorder, and Dissatisfies with
Looks
2 - 16
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Figure SIA2.1b MINITAB pie charts for
Gender, Disorder, and Dissatisfies with
Looks
2 - 17
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Figure SIA2.1c MINITAB pie charts for
Gender, Disorder, and Dissatisfies with
Looks
2 - 18
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Figure SIA2.2 MINITAB side-by-side pie
charts for Dissatisfied with Looks by Gender
2 - 19
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Figure SIA2.3 MINITAB side-by-side Pie
charts for Dissatisfied with Looks by
Comorbid Disorder
2 - 20
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2.2
Graphical Methods for Describing
Quantitative Data
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Table 2.2
2 - 22
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Figure 2.8 MINITAB dot plot for 100 EPA
mileage ratings
2 - 23
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Figure 2.9 MINITAB stem-and-leaf display
for 100 mileage ratings
2 - 24
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Figure 2.10 SPSS histogram for 100 EPA
gas mileage ratings
2 - 25
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Table 2.3
2 - 26
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Figure 2.11 The effect of the size of a data
set on the outline of a histogram
2 - 27
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Procedure
2 - 28
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Table 2.4
2 - 29
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Figure 2.12 SPSS histogram for task
deviations
2 - 30
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Figure 2.13 MINITAB stem-and-leaf display
for task deviations
2 - 31
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Definition
2 - 32
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Figure SIA2.4 MINITAB side-by-side
histograms for Appearance Evaluation by
Gender
2 - 33
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2.3
Summation Notation
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2.4
Numerical Measures of Central Tendency
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Figure 2.14 Numerical descriptive
measures
2 - 36
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Definition
2 - 37
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Formula
2 - 38
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Figure 2.15 SAS numerical descriptive
measures for 100 EPA gas mileages
2 - 39
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Definition
2 - 40
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Definition
2 - 41
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Figure 2.16 Location of the Median
2 - 42
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Procedure
2 - 43
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Definition
2 - 44
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Procedure
2 - 45
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Definition
2 - 46
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Figure 2.17 MINITAB descriptive statistics
for earthquake data
2 - 47
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Figure 2.18a MINITAB Histogram for
Magnitudes of Aftershocks
2 - 48
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Figure 2.18b MINITAB Histogram for InterArrival Times of Aftershocks
2 - 49
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2.5
Numerical Measures of Variability
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Figure 2.19 Response time histograms for
two drugs
2 - 51
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Definition
2 - 52
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Table 2.5
2 - 53
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Figure 2.20 Dot plots for deviations in Table
2.5
2 - 54
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Definition
2 - 55
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Formula
2 - 56
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Definition
2 - 57
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Definition
2 - 58
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Figure 2.21 Reproduction of SAS numerical
descriptive measures for 100 EPA mileages
2 - 59
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2.6
Interpreting the Standard Deviation
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Table 2.6
2 - 61
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Table 2.7
2 - 62
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Table 2.8
2 - 63
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Figure 2.22 MINITAB descriptive statistics
for rat maze times
2 - 64
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Figure 2.23 MINITAB histogram of rat maze
times
2 - 65
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Figure 2.24 The relation between the range
and the standard deviation
2 - 66
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Figure 2.25 Battery life-length distribution:
manufacturer’s claim assumed true
2 - 67
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Figure SIA2.5 MINITAB descriptive
statistics for appearance evaluation by
gender
2 - 68
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2.7
Numerical Measures of Relative Standing
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Figure 2.26 Location of 90th percentile for
test grades
2 - 70
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Definition
2 - 71
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Figure 2.27 SPSS percentile statistics for
water-level task deviations
2 - 72
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Figure 2.28 The quartile for a data set
2 - 73
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Definition
2 - 74
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Formula
2 - 75
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Figure 2.29 Verbal SAT scores of high
school seniors
2 - 76
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Definition
2 - 77
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Figure 2.30 Population z-scores for a
mound–shaped distribution
2 - 78
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2.8
Methods for Detecting Outliers:
Box plots and z-Scores
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Definition
2 - 80
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Definition
2 - 81
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Figure 2.31 Annotated MINITAB box plot for
EPA gas mileages
2 - 82
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Definition
2 - 83
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Definition
2 - 84
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Figure 2.32 MINITAB box plot for waterlevel task deviations
2 - 85
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Table 2.9
2 - 86
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Figure 2.33 SAS box plots for reaction-time
data
2 - 87
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Figure 2.34 Male salary distribution
2 - 88
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Procedure
2 - 89
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Figure SIA2.6 MINITAB box plots for
Appearance Evaluation score by Gender
2 - 90
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2.9
Graphing Bivariate Relationships (Optional)
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Figure 2.35 Scatterplot of cost vs. floor area
2 - 92
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Figure 2.36 Hypothetical bivariate
relationship
2 - 93
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Table 2.10
2 - 94
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Figure 2.37 SPSS scatterplot for medical
factors data in Table 2.10
2 - 95
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2.10
Distorting the Truth with Descriptive
Statistics
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Table 2.11
2 - 97
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Figure 2.38 MINITAB bar graph of vessel
collisions by location
2 - 98
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Figure 2.39 SPSS bar graph of vessel
collisions by location, with adjusted vertical
axis
2 - 99
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Figure 2.40 Relative frequency of fatal motor
vehicle accidents on each of four major
highways
2 - 100
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Figure 2.41 Mileage distributions for two car
models
2 - 101
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