Basic Data Analysis:Descriptive Statistics

Ch 15 2

Coding Data and the Data Code Book

• Data entry refers to the creation of a computer file that holds the raw data taken from all of the questionnaires deemed suitable for analysis

• Data coding refers to the identification of codes that pertain to the possible responses for each question on the questionnaire

• Data code book identifies all of the variable names and code numbers associated with each possible response to each question that makes up the data set

Ch 15 3

Ch 15 4

Types of Statistical Analyses Used in Marketing Research

• Data summarization: the process of describing a data matrix by computing a small number of measures that characterize the data set

Ch 15 5

Types of Statistical Analyses Used in Marketing Research

• Four functions of data summarization:

– Summarizes the data

– Applies understandable conceptualizations

– Communicates underlying patterns

– Generalizes sample findings to the population

Ch 15 6

Why is Statistical Analysis Used?

• Why Use Statistical Analysis?

– To summarize data • The average price of a Gateway PC

is $2,489• The low is $999, and the high is

$4,678: this is the range• The mode is $2,200

Ch 15 7

Why is Statistical Analysis Used?

• Why Use Statistical Analysis?

– To show basic patterns in the data• 30% buys at $1,500 or less• 50% buys at between $2,500 and

$1,500• 20% buys at $2,500 or more

Ch 15 8

Why is Statistical Analysis Used?

• Why Use Statistical Analysis?

– To interpret these patterns• The majority of Gateway buyers pay

$2,500 or less

Ch 15 9

Why is Statistical Analysis Used?

• Why Use Statistical Analysis?

– To generalize the patterns to the population• 95% of all Gateway buyers pay

between $2,000 and $3,000 for their PC’s

Ch 15 10

Types of Statistical Analyses Used in Marketing Research

• Statistical Analysis:

Ch 15 11

Types of Statistical Analyses Used in Marketing Research

• Five Types of Statistical Analysis:

1. Descriptive analysis: used to describe the data set

2. Inferential analysis: used to generate conclusions about the population’s characteristics based on the sample data

Ch 15 12

Types of Statistical Analyses Used in Marketing Research3. Differences analysis: used to

compare the mean of the responses of one group to that of another group

4. Associative analysis: determines the strength and direction of relationships between two or more variables

Ch 15 13

Types of Statistical Analyses Used in Marketing Research5. Predictive analysis: allows one to

make forecasts for future events

Ch 15 14

Understanding Data Via Descriptive Analysis

• Two sets of descriptive measures:

– Measures of central tendency: used to report a single piece of information that describes the most typical response to a question

– Measures of variability: used to reveal the typical difference between the values in a set of values

Ch 15 15

Understanding Data Via Descriptive Analysis

• Measures of Central Tendency:

– Mode: the value in a string of numbers that occurs most often

– Median: the value whose occurrence lies in the middle of a set of ordered values

– Mean: sometimes referred to as the “arithmetic mean”; the average value characterizing a set of numbers

Ch 15 16

Understanding Data Via Descriptive Analysis

• Measures of Variability:– Frequency distribution reveals the number

(percent) of occurrences of each number or set of numbers

– Range identifies the maximum and minimum values in a set of numbers

– Standard deviation indicates the degree of variation in a way that can be translated into a bell-shaped curve distribution

Ch 15 17

Understanding Data Via Descriptive Analysis

• Measures of Variability:

Ch 15 18

When to Use a Particular Statistic