Practical Statistics Descriptive Statistics

There are six statistics that will answer 90% of all questions!

There six are: 1. Descriptive

There six are: 1. Descriptive 2. Chi-square

There six are: 1. Descriptive 2. Chi-square 3. Z-tests

There six are: 1. Descriptive 2. Chi-square 3. Z-tests 4. t-tests

There six are: 5. Correlation (association)

There six are: 5. Correlation 6. Regression

Descriptive Statistics These are utilized to describe the characteristic of a population (parameter), or the characteristics of a sample (a statistic) Many business problems can be solved by knowing only descriptive statistics.

Geodemography

Geodemography

Descriptive Statistics Simple counts: frequency

Descriptive Statistics Simple counts: frequency The amount of time (in seconds) needed for assembly-line workers to complete a weld was recorded for 40 workers a. What is the frequency for each amount of time?

Descriptive Statistics Simple counts: histograms

Descriptive Statistics Simple counts: histograms

Descriptive Statistics Simple counts: ogive

Symmetry

Right Left

Descriptive Statistics Back to the workers making welds….. The amount of time (in seconds) needed for assembly-line workers to complete a weld was recorded for 40 workers

Descriptive Statistics Central tendency: A single number to represent a group.

Descriptive Statistics The standard deviation is The average is The amount of time (in seconds) needed for assembly-line workers to complete a weld was recorded for 40 workers

Descriptive Statistics Central tendency: 1. Mode The most frequent score.

Descriptive Statistics Central tendency: 1. Mode 2. Median Half the numbers are larger, half are smaller.

Descriptive Statistics Central tendency: 1. Mode 2. Median 3. Mean The center of gravity of a distribution

Descriptive Statistics Central tendency: 1. Mode 2. Median 3. Mean Arithmetic Harmonic Geometric

Descriptive Statistics Central tendency: 1. Mode 2. Median 3. Mean Arithmetic

Descriptive Statistics Central tendency: 3. Mean Harmonic

Descriptive Statistics Central tendency: 3. Mean Harmonic

Descriptive Statistics Central tendency: 1. Mode 2. Median 3. Mean Harmonic

Descriptive Statistics Central tendency: 1. Mode 2. Median 3. Mean Geometrical (For ratio numbers)

Geometric Mean: Does pricing following perception or volume? If a package holds twice as much, should it be priced as twice that of a package that holds half as much?

Problem: Customers do not perceive volume correctly.

Geometric Mean: Does pricing following perception or volume? The perception of volume follows: Seven’s Law: How should this be done?

Descriptive Statistics Measure of Variation: Again a single number to represent a group.

Population: mean = 10 SD = 5

Population: mean = 10 SD = 2.5

Population: mean = 10 SD = 1

Population: mean = 10 SD = 0.5

Descriptive Statistics Measure of Variation: 1. Range a. (Highest – Lowest) + 1 b. Subject to deviancy

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation a. Problem: Variation logically would be the average deviation around a measure of central tendency.

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation a. Problem: But… Always!!

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation a. Problem: So negative can be removed by looking at the absolute value.

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation a. Problem: Negative can be removed by squaring the value.

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation a. Problem: This is the definition of: 3. Variance

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation 3. Variance a. Problem: This is difficult to work with descriptively, so the square root can be taken.

Descriptive Statistics Measure of Variation: 1. Range 2. Mean Deviation 3. Variance a. This is called the: 4. Standard Deviation

The standard deviation is: Roughly the average difference scores are from the average. Or: It is roughly the average difference between two measures taken from the same population. It is an intuitive measure.

The amount of time (in seconds) needed for assembly-line workers to complete a weld was recorded for 40 workers Back to our welding times…..

a.Give the central tendency measures of this sample. b.What is the range, variance and standard deviation? c.Explain what you now know about the time it takes to make welds. d. When should a worker be reprimanded or fired for working too slow?

a.Give the central tendency measures of this sample.

b.What is the range, variance and standard deviation?

a.Give the central tendency measures of this sample. b.What is the range, variance and standard deviation? c.Explain what you now know about the time it takes to make welds.

a.Give the central tendency measures of this sample. b.What is the range, variance and standard deviation? c.Explain what you now know about the time it takes to make welds. d.When should a worker be reprimanded or fired for working too slow?

Service Encounter and Personality How many respondents do we have, and what is their sex?

Service Encounter and Personality What is their average age?

Service Encounter and Personality How satisfied were they with their service encounter?

Service Encounter and Personality How satisfied were they with their service encounter?