Practical Statistics

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Practical Statistics

• Descriptive Statistics

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

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• There six are
• Descriptive
• Chi-square

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• There six are
• Descriptive
• Chi-square
• Z-tests

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• There six are
• Descriptive
• Chi-square
• Z-tests
• t-tests

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• There six are
• 5. Correlation (association)

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• There six are
• 5. Correlation
• 6. Regression

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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.
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Geodemography
http//www.youtube.com/watch?v7UCxzYpXhpI
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Geodemography
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Geodemography
2012 Map http//www.geocurrents.info/2012/11!gal
lery/6/
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Descriptive Statistics Simple counts frequency
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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. 69 60 75 74 68 66 73
76 63 67 69 73 65 61 73 72 72 65 69 70 64 61 74
76 72 74 65 63 69 73 75 70 60 62 68 74 71 73 68
67 a. What is the frequency for each amount of
time?
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Descriptive Statistics Simple counts histograms
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Open the file called WeldDat.sav Do the
following Graphs Graphboard Template
Select WeldTime Select histogram
with Normal OK
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Descriptive Statistics Simple counts histograms
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Descriptive Statistics Simple counts ogive
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Descriptive Statistics Simple counts ogive
http//mathworld.wolfram.com/Ogive.html
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Symmetry
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Right
Left
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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. 69 60 75 74
68 66 73 76 63 67 69 73 65 61 73 72 72 65 69 70
64 61 74 76 72 74 65 63 69 73 75 70 60 62 68 74
71 73 68 67
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Descriptive Statistics Central tendency A
single number to represent a group.
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Descriptive Statistics The average is 68.98.
The standard deviation is 4.77. The amount of
time (in seconds) needed for assembly-line
workers to complete a weld was recorded for 40
workers. 69 60 75 74 68 66 73 76 63 67 69 73 65
61 73 72 72 65 69 70 64 61 74 76 72 74 65 63 69
73 75 70 60 62 68 74 71 73 68 67
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• Descriptive Statistics
• Central tendency
• 1. Mode
• The most frequent score.

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

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

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

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

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Descriptive Statistics Central tendency 3.
Mean Harmonic
Clayson Power Data
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Descriptive Statistics Central tendency 3.
Mean Harmonic
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Descriptive Statistics Central tendency 3.
Mean Harmonic
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Descriptive Statistics Central tendency 1.
Mode 2. Median 3. Mean Harmonic
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Descriptive Statistics Central tendency 1.
Mode 2. Median 3. Mean Geometrical (For
pure ratio numbers)
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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?
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Problem Customers do not perceive volume
correctly.
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Geometric Mean Does pricing following
perception or volume? The perception of volume
follows Sevens Law
How should this be done?
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Descriptive Statistics Measure of Variation
Again a single number to represent a group.
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• Descriptive Statistics
• Measure of Variation
• Range
• a. (Highest Lowest) 1
• b. Subject to deviancy

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

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• Descriptive Statistics
• Measure of Variation
• Range
• Mean Deviation
• a. Problem But

Always!!
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• Descriptive Statistics
• Measure of Variation
• Range
• Mean Deviation
• a. Problem So negative can be removed by
• looking at the absolute value.

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

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

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

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

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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.
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The amount of time (in seconds) needed for
assembly-line workers to complete a weld was
recorded for 40 workers. 69 60 75 74 68 66 73
76 63 67 69 73 65 61 73 72 72 65 69 70 64 61 74
76 72 74 65 63 69 73 75 70 60 62 68 74 71 73 68
67
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• Give the central tendency measures of this
  sample.
• What is the range, variance and standard
  deviation?
• 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?

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• Give the central tendency measures of this
  sample.

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1. Give the central tendency measures of this
   sample.
2. What is the range, variance and standard
   deviation?

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

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