Chapter Fourteen Data Processing and Fundamental Data Analysis

Chapter Fourteen Data Processing and Fundamental Data Analysis Copyright © 2004 John Wiley & Sons, Inc.

Learning Objectives Learning Objective 1. To get an overview of the data analysis procedure. 2. To develop an understanding of the importance and nature of quality control checks. 3. To understand the data entry process and data entry alternatives. 4. To learn how surveys are tabulated and crosstabulated. 5. To learn how to set up and interpret crosstabulations. 6. To comprehend the basic techniques of statistical analysis. John Wiley & Son, Inc. 2

The Data Analysis Procedure Learning Objective To get an overview of the data analysis procedure • Five Step Procedure for Data Analysis – Step One: Validation and editing (quality control) – Step Two: Coding – Step Three: Data Entry – Step Four: Machine Cleaning of Data – Step Five: Tabulation and Statistical Analysis John Wiley & Son, Inc. 3

Step One: Validation and Editing Learning Objective To understand the importance and nature of quality control checks. • Validation – The process of ascertaining that interviews actually were conducted as specified. – Telephone Validation • • Was the person actually interviewed? Was the respondent actually qualified? Was the interview conducted in the required manner? Did the interviewer cover the entire survey? – Check for other types of problems – Purpose of the Validation John Wiley & Son, Inc. 4

Step One: Validation and Editing • • Learning Objective To understand the importance and nature of quality control checks. Editing Checking for interviewer mistakes 1. Did the interviewer ask or record answers for certain questions? 2. Questionnaires are checked to make sure Skip patterns are followed. 3. Responses to open-ended responses are checked. John Wiley & Son, Inc. 5

Coding • Learning Objective To understand the data-entry process and data-entry alternatives. Coding Defined – Grouping and assigning numeric codes to the responses • The Coding Process 1. 2. 3. 4. • Listing responses Consolidating responses Setting codes Entering codes Automated Coding Systems John Wiley & Son, Inc. 6

Data Entry Learning Objective To understand the data-entry process and data-entry alternatives. • Data Entry – Process of converting information to a form that can be read by a computer • Intelligent Data Entry – The checking of information being entered for internal logic by either that data entry device or another device connected to it. • The Data Entry Process – The mechanics of the process. – The validated, edited, and coded questionnaires are given to a data entry operator. – The process of going directly from the questionnaire to the data entry device and storage medium is more accurate and efficient. John Wiley & Son, Inc. 7

Data Entry Learning Objective To understand the data-entry process and data-entry alternatives. • Scanning – Optical Scanning – Technology of this type—been around for years – Electronically Captured Data is Increasing • • Computer-assisted telephone interviewing Internet surveys Disks-by-mail surveys Touch. Screen Kiosk surveys John Wiley & Son, Inc. 8

Machine Cleaning of Data Learning Objective To understand the data-entry process and data-entry alternatives. • Machine Cleaning of Data – A final computerized error check of data. • Error Checking Routines – Check for logical errors in the data • Marginal Report – A computer-generated table of the frequencies of the responses to each question to monitor entry of valid codes and correct use of skip patterns. • Final Error Check in the Process – Should be ready for tabulation and statistical analysis John Wiley & Son, Inc. 9

Tabulation of Survey Results • To learn how surveys are tabulated. One Way Frequency Tables – • Learning Objective A table showing the number of responses to each answer. Base for Percentages 1. Total respondents 2. Number of people asked the question 3. Number of people answering the question • Selecting the Base for One-Way Frequency Tables Showing Results from Multiple-Choice Questions John Wiley & Son, Inc. 10

Tabulation of Survey Results Learning Objective To learn how to set up and interpret crosstabulations. • Cross-Tabulations • Examination of the responses of one question relative to responses to one or more other questions. – Three different percentages calculated for each cell in a crosstabulation table (see exhibit 14. 2) • Column percentage • Row percentage • Total percentages • Stub and Banner Table—see exhibit 14. 13 John Wiley & Son, Inc. 11

Graphic Representations of Data Learning Objective To comprehend the basic techniques of statistical analysis. • Line Charts – The simplest form of graphs. • Pie Charts – Appropriate for displaying marketing research results in a wide range of situations. • Bar Charts 1. Plain bar chart 2. Clustered bar charts 3. Stacked bar charts 4. Multiple row, three-dimensional bar charts John Wiley & Son, Inc. 12

Descriptive Statistics Learning Objective To comprehend the basic techniques of statistical analysis. • Measures of Central Tendency – Nominal and Ordinal Scales – Interval and Ratio Scales – Mean – Median – Mode John Wiley & Son, Inc. 13

Learning Objective Descriptive Statistics To comprehend the basic techniques of statistical analysis. Measures of Central Tendency • Mean h X where = I=1 f i. X i n fi = the frequency of the ith class Xi = the midpoint of that class h = the number of classes n = the total number of observations John Wiley & Son, Inc. 14

Learning Objective Descriptive Statistics To comprehend the basic techniques of statistical analysis. Measures of Dispersion Standard deviation S = where √ n I=1 (Xi - X) 2 n-1 S = sample standard deviation Xi = the value of the ith observation X = the sample mean n = the sample size John Wiley & Son, Inc. 15

Descriptive Statistics Learning Objective To comprehend the basic techniques of statistical analysis. • Measures of Dispersion – Variance • The sums of the squared deviations from the mean divided by the number of observations minus one. • The same formula as standard deviation with the squareroot sign removed. – Range • The maximum value for a variable minus the minimum value for that variable John Wiley & Son, Inc. 16

Descriptive Statistics Learning Objective To comprehend the basic techniques of statistical analysis. • Means, Percentages, and Statistical Tests – Whether to use measures of central tendency or percentages. – Responses are either categorical or take the form of continuous variables – Variables such as age can be continuous or categorical. – If categories are used, one-way frequency distributions and crosstabulations are the most obvious choices. – Continuous data can be put into categories. John Wiley & Son, Inc. 17

SUMMARY • • Learning Objective Overview of the Data Analysis Procedure Step One: Validation and Editing Step Two: Coding Step Three: Data Entry Step Four: Machine Cleaning of Data Step Five: Tabulation and Statistical Analysis Graphic Representations of Data Descriptive Statistics John Wiley & Son, Inc. 18

Learning Objective The End Copyright © 2004 John Wiley & Son, Inc. 19