Basic data Analysis

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• Basic data Analysis
• Chapter 19 Editing and Coding
• Chapter 20 Descriptive Data Analysis

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Stages of Data Analysis
EDITING
ERROR CHECKING AND VERIFICATION
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Editing

• The process of checking for omissions,
  legibility, consistency and adjusting the data
• And readying them for coding and storage

Coding
The process of identifying and assigning a
numerical score or other character symbol to
previously edited data
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Birth Year Recorded by Interviewer

• 1850?
• 1950 more likely

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Editing
FIELD EDITING
IN-HOUSE EDITING
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Reasons for Editing
QUESTIONS ANSWERED OUT OF ORDER
CONSISTENCY
COMPLETENESS

• Out of order
• Ranking? choice
• Choice? checklist
• DK
• Legitimate dont know
• Reluctant dont know
• Confused dont know

Plug value Discarding

• Example
• Five million
• 5,000,000
• 5 M
• Others, specify..

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Codes

• The rules for interpreting, classifying, and
  recording data in the coding process
• The actual numerical or other character symbols

1a. How many years have you been playing tennis
on a regular basis? Number of years
__________ b. What is your level of
play? Novice . . . . . . . . . . . . . . .
-1 Advanced . . . . . . . -4 Lower Intermediate
. . . . . -2 Expert . . . . . . . . . -5 Upper
Intermediate . . . . . -3 Teaching Pro . . . .
-6 c. In the last 12 months, has your level
of play improved, remained the same or
decreased? Improved. . . . . . . . . . . . .
. -1 Decreased. . . . . . . -3 Remained the
same . . . . . -2
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I believe that people judge your success by the
kind of car you drive.

• Strongly agree
• Mildly agree
• Neutral
• Mildly disagree
• Strongly disagree

1 2 3 4 5
5 4 3 2 1
2 1 0 -1 -2
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Tips

• Rules for Coding
• Categories should be exhaustive
• Categories should be mutually exclusive and
  independent
• Coding Open-Ended Responses
• Code book
• Identifies each variable
• Provides a variables description
• Identifies each code name and position on storage
  medium

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Data Entry

• The process of transforming data from the
  research project to computers.
• Recoding is the process of using a computer to
  convert original codes used for raw data to codes
  that are more suitable for analysis.
• Var11 8 - Var1
• Error Checking and Verification
• Data cleaning

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Descriptive Analysis

• The transformation of raw data into a form that
  will make them easy to understand and interpret
  rearranging, ordering, and manipulating data to
  generate descriptive information

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Type of descriptive analysis
Type of Measurement
Frequency table Proportion (percentage) Frequency
table Category proportions (percentages) Mode
Two categories
Nominal
More than two categories
Rank order Median
Ordinal
Arithmetic mean
Interval
Index numbers Geometric mean Harmonic mean
Ratio
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Tabulation

• Tabulation - Orderly arrangement of data in a
  table or other summary format
• FREQUENCY TABLE
• The arrangement of statistical data in a
  row-and-column format that exhibits the count of
  responses or observations for each category
  assigned to a variable
• PERCENTAGES
• CENTRAL TENDENCY

Type of Scale Measure of
Measure of Central Tendency
Dispersion Nominal Mode None Ordin
al Median Percentile Interval or
ratio Mean Standard deviation
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Questionnaire An Example
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Questionnaire An Example
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Descriptive data analysis Sample profile
Calculated from total respondents
Calculated from respondents excluding missing
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Descriptive data analysis Sample profile
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Descriptive data analysis
Nominal scale data
Interval scale data
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CROSS-TABULATION

• ANALYZE DATA BY GROUPS OR CATEGORIES
• COMPARE DIFFERENCES
• CONTINGENCY TABLE
• PERCENTAGE CROSS-TABULATIONS

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PERCENTAGE CROSS TABULATION
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ELABORATION AND REFINEMENT

• MODERATOR VARIABLE
• A third variable that, when introduced into an
  analysis, alters or has a contingent effect on
  the relationship between an independent variable
  and a dependent variable.
• SPURIOUS RELATIONSHIP
• An apparent relationship between two variables
  that is not authentic.

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Elaborative Analysis an example
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Quadrant Analysis
Importance
High Low
1,7 Easy to prepare
6,6 good taste
1,2 Fancy meal
5,2 Late night snack
Low Purchasing intention
High
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DATA TRANSFORMATION

• Data conversion
• Changing original form of the data to a new
  format with a more appropriate data analysis form
• Obtained a new variable
• COLLAPSING A FIVE POINT SCALE an example

• STRONGLY AGREE
• AGREE
• NEITHER AGREE OR DISAGREE
• DISAGREE
• STRONGLY DISAGREE

• AGREE
• NEUTRAL
• DISAGREE

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INDEX NUMBERS

• Score or observation recalibrated to indicate how
  it relates to a base number
• CPI - Consumer Price Index

Area1 41.01 0.7832 x 100
78.32 52.36 Area2 47.58 0.9087 x 100
90.87 52.36 Area3 60.49 1.1553 x 100
115.53 52.36 Total US 52.36 1.0000 x
100 100.00 average 52.36
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CALCULATING RANK ORDER Example

• Rank the most favorite place you would like to go
  on your vacation
• (1most preference, 4least preference)

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CHARTS AND GRAPHS

• PIE CHARTS
• LINE GRAPHS
• BAR CHARTS
• VERTICAL
• HORIZONTAL

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COMPUTER PROGRAMS

• SPSS
• SAS
• SYSTAT
• MICROSOFT EXCEL

Data Interpretation

• The process of making pertinent inferences and
  drawing conclusions
• Concerning the meaning and implications of a
  research investigation