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Practical Statistics

Practical Statistics. Descriptive Statistics. There are six statistics that will answer 90% of all questions!. There six are: Descriptive. There six are: Descriptive Chi-square. There six are: Descriptive Chi-square Z-tests. There six are: Descriptive Chi-square

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Practical Statistics

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  1. Practical Statistics Descriptive Statistics

  2. There are six statistics that will answer90% of all questions!

  3. There six are: • Descriptive

  4. There six are: • Descriptive • Chi-square

  5. There six are: • Descriptive • Chi-square • Z-tests

  6. There six are: • Descriptive • Chi-square • Z-tests • t-tests

  7. There six are: • 5. Correlation (association)

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

  9. 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.

  10. Geodemography http://www.youtube.com/watch?v=7UCxzYpXhpI

  11. Geodemography

  12. Descriptive Statistics Simple counts: frequency

  13. 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?

  14. Descriptive Statistics Simple counts: histograms

  15. Descriptive Statistics Simple counts: histograms

  16. Descriptive Statistics Simple counts: ogive http://mathworld.wolfram.com/Ogive.html

  17. Symmetry

  18. Right Left

  19. 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

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

  21. Descriptive Statistics The standard deviation is 4.77. The average is 68.98. 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

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

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

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

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

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

  27. Descriptive Statistics Central tendency: 3. Mean Harmonic

  28. Descriptive Statistics Central tendency: 3. Mean Harmonic

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

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

  31. 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?

  32. Problem: Customers do not perceive volume correctly.

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

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

  35. Population: mean = 10 SD = 5

  36. Population: mean = 10 SD = 2.5

  37. Population: mean = 10 SD = 1

  38. Population: mean = 10 SD = 0.5

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

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

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

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

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

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

  45. 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.

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

  47. The standard deviationis: 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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