第 6章 资料结构
Data Structures:
Classifying the Various Types of Data Sets
基本术语
?数据集合
? Measurements of items
? e.g.,Yearly sales volume for your 23 salespeople
? e.g.,Cost and number produced,daily,for the past month
?基本单元
? The items being measured
? e.g.,Salespeople,Days,Companies,Catalogs,…
?变量
? The type of measurement being done
? e.g.,Sales volume,Cost,Productivity,Number of defects,…
?Univariate data set,One variable measured for each
elementary unit（ 单变量 ）
? e.g.,Sales for the top 30 computer companies.
? Can do,Typical summary,diversity,special features
?Bivariate data set,Two variables（ 双变量 ）
? e.g.,Sales and Employees for top 30 computer firms
? Can also do,relationship,prediction
?Multivariate data set,Three or more variables（ 多变量 ）
? e.g.,Sales,Employees,Inventories,Profits,…
? Can also do,predict one from all other variables
有哪些变量?
数值型或分类型（ Categories）
?Quantitative Variable,计量型或尺度型
? e.g.,Sales,# Employees
? Can add,rank,count
?Qualitative Variable,分类型（有序、名义）
? Ordinal Variable,Categories with meaningful ordering
? e.g.,Bond rating (AA,A,B,…),Diamonds (VSI,SI,…)
? Can rank,count
? Nominal Variable,categories without meaningful ordering
? e.g.,State,Type of business,Field of study
? Can count
时间序列型或横截面型
Time-Series or Cross-Sectional?
?Time-Series Data,Data values recorded in meaningful
sequence such as stock market index et.al..
? Elementary units might be days or quarters or years
? e.g.,Daily Dow-Jones stock market average close for the past 90
days
? e.g.,Your firm’s quarterly sales over the past 5 years
?Cross-Sectional Data,No meaningful sequence
? e.g.,Sales of 30 companies
? e.g.,Productivity of each sales division
? Easier than time series!
Example-1
Firm Sales Industry Group S&P Rating
IBM 66,346 Office Equipment A
Exxon 59,023 Fuel A-
GE 40,482 Conglomerates A+
AT&T 34,357 Telecommunications A-
S&P,Standard & Poor’s
Example (续 )
Firm Sales Industry Group S&P Rating
IBM 66,346 Office Equipment A
Exxon 59,023 Fuel A-
GE 40,482 Conglomerates A+
AT&T 34,357 Telecommunications A-
Multivariate Data (3 variables)
Elementary
units
Quantitative
variable
Nominal
Qualitative
variable
Ordinal
Qualitative
variable
Example-2
Year Small Business Administration
Budget ($ Millions)
1991 464
1992 1,891
1993 1,177
1994 2,058
1995 798
1996 749
Example(continued)
Year Small Business Administration
Budget ($ Millions)
1991 464
1992 1,891
1993 1,177
1994 2,058
1995 798
1996 749
Elementary unit
defined by,year”
Quantitative data
Data Structures:
Classifying the Various Types of Data Sets
基本术语
?数据集合
? Measurements of items
? e.g.,Yearly sales volume for your 23 salespeople
? e.g.,Cost and number produced,daily,for the past month
?基本单元
? The items being measured
? e.g.,Salespeople,Days,Companies,Catalogs,…
?变量
? The type of measurement being done
? e.g.,Sales volume,Cost,Productivity,Number of defects,…
?Univariate data set,One variable measured for each
elementary unit（ 单变量 ）
? e.g.,Sales for the top 30 computer companies.
? Can do,Typical summary,diversity,special features
?Bivariate data set,Two variables（ 双变量 ）
? e.g.,Sales and Employees for top 30 computer firms
? Can also do,relationship,prediction
?Multivariate data set,Three or more variables（ 多变量 ）
? e.g.,Sales,Employees,Inventories,Profits,…
? Can also do,predict one from all other variables
有哪些变量?
数值型或分类型（ Categories）
?Quantitative Variable,计量型或尺度型
? e.g.,Sales,# Employees
? Can add,rank,count
?Qualitative Variable,分类型（有序、名义）
? Ordinal Variable,Categories with meaningful ordering
? e.g.,Bond rating (AA,A,B,…),Diamonds (VSI,SI,…)
? Can rank,count
? Nominal Variable,categories without meaningful ordering
? e.g.,State,Type of business,Field of study
? Can count
时间序列型或横截面型
Time-Series or Cross-Sectional?
?Time-Series Data,Data values recorded in meaningful
sequence such as stock market index et.al..
? Elementary units might be days or quarters or years
? e.g.,Daily Dow-Jones stock market average close for the past 90
days
? e.g.,Your firm’s quarterly sales over the past 5 years
?Cross-Sectional Data,No meaningful sequence
? e.g.,Sales of 30 companies
? e.g.,Productivity of each sales division
? Easier than time series!
Example-1
Firm Sales Industry Group S&P Rating
IBM 66,346 Office Equipment A
Exxon 59,023 Fuel A-
GE 40,482 Conglomerates A+
AT&T 34,357 Telecommunications A-
S&P,Standard & Poor’s
Example (续 )
Firm Sales Industry Group S&P Rating
IBM 66,346 Office Equipment A
Exxon 59,023 Fuel A-
GE 40,482 Conglomerates A+
AT&T 34,357 Telecommunications A-
Multivariate Data (3 variables)
Elementary
units
Quantitative
variable
Nominal
Qualitative
variable
Ordinal
Qualitative
variable
Example-2
Year Small Business Administration
Budget ($ Millions)
1991 464
1992 1,891
1993 1,177
1994 2,058
1995 798
1996 749
Example(continued)
Year Small Business Administration
Budget ($ Millions)
1991 464
1992 1,891
1993 1,177
1994 2,058
1995 798
1996 749
Elementary unit
defined by,year”
Quantitative data
