文档介绍：CHAPTER 4: Data Collection and Sampling Methods
to pany
Introduction to Business Statistics
fourth edition, by Ronald M. Weiers
Presentation by Priscilla Chaffe-Stengel
Donald N. Stengel
© 2002 The Wadsworth Group
Chapter 4 - Learning Objectives
Describe the types of studies and their purposes:
Exploratory
Descriptive
Causal
Predictive
Explain the differences between data sources:
Primary
Secondary: Internal versus External
Differentiate between sampling designs:
Probabilitistic versus nonprobabilitistic designs
Differentiate between sampling and nonsampling errors.
© 2002 The Wadsworth Group
Chapter 4 - Key Terms
Error
Sampling
Nonsampling
Types of Studies
Exploratory
Descriptive
Causal
Predictive
Types of Data
Primary
Secondary
Internal vs External
Probability sample
Simple random sample
Systematic sample
Stratified sample
Cluster sample
Nonprobability sample
Convenience sample
Quota sample
Purposive sample
Judgment sample
© 2002 The Wadsworth Group
Types of Studies
Exploratory
Understand a problem, identify relevant variables, formulate hypotheses
Descriptive
Establish reliable measurements
Causal
Determine relationships among variables
Predictive
Use analysis to forecast
© 2002 The Wadsworth Group
Sources of Data
Primary
Data generated by the researcher for this study
Survey, experimental, observational research most popular
Tend to require more time and expense than secondary data
Secondary
Data gathered from another source or for another purpose
Internal sources within the researcher’anization
External sources, including governmental, trade, commercial and sources
© 2002 The Wadsworth Group
Types and Sources of Error
Sampling Error
Random, nondirectional
When a sample is used instead of a census
Nonsampling Error
Directional bias overstating or understating the true population parameter
Potential sources:
Poor sample design
Poor measurement
Poor instrumentation
© 2002 The Wadsworth Group
Types of Samples
Simple random
Systematic
Every