SESSION 3 & 4 Last Update 15 th February 2011 Introduction to Statistics

Lecturer:Florian Boehlandt University:University of Stellenbosch Business School Domain:

Data Collection Methods Data Collection  Primary Data Direct observation  Observational Data - Inconclusive: Cause – Effect Relationship? + Inexpensive

Data Collection Methods Experiments  Experimental Data: Experimental group and control group - Expensive (controlled environement) + Unbiased

Data Collection Methods Surveys: Market research to determine preferences and attitudes of consumers. Solicit demographic information to adapt products / advertisements to customer preference. - Response Rate+ inexpensive

Surveys Personal Interviews - Biasing responses (leading questions) - Expensive + prepared questions + higher response rate + fewer incorrect responses Telephone Interviews - Low response rate+ Inexpensive

Surveys Self-Administered Survey Self-Administered questionnaire mailed to sample of people - Incorrect answers (misleading questions) + Useful when required samples are large

Questionnaire Design 1.Short 2.Simple, short, clearly worded, unambiguous questions 3.Demographic questions (sub-samples) 4.Dichotomous questions or multiple-choice 5.Open-ended questions (to supplement above) 6.Avoid leading questions 7.Pretest questionnaire using a small sample 8.Questions should address a single issue 9.Think about desired data types (interval / nominal) and the statistical techniques (descriptive / inferential) when formulating questions

Questionnaire Layout 1.Spacing 2.Photo-reduction 3.Alignment and consistent positioning to avoid involuntary omission 4.Easy questions first (i.e. demographic questions)

Questionnaires + As a basis for interviews- Design? + Posted / ed- Simplicity? + Large samples- Low response rate + Inexpensive- Time delay (response speed) + No prior arrangements- Literacy problems + Respondents may be more honest (anonymity) - No controlled environment + No interviewer bias- Incomplete questionnaires - Independent replies

Interviews + Accuracy- Time consuming + Response Rate- Expensive + Completeness and response speed - Respondent bias + Follow-up questions- Transcription / analysis  not unbiased + Characteristics of respondent assessed – tone of voice, facial expression, hesitation