1. Practical Statistics Descriptive Statistics

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

3. There six are: 1. Descriptive

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

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

6. There six are: 1. Descriptive 2. Chi-square 3. Z-tests 4. 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. 2012 Map http://www.geocurrents.info/2012/11#!gallery/6/

13. Descriptive Statistics Simple counts: frequency

14. 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?

15. Descriptive Statistics Simple counts: histograms

16. Open the file called WeldDat.sav Do the following: Graphs Graphboard Template… Select WeldTime Select histogram with Normal… OK

17. Descriptive Statistics Simple counts: histograms

18. Descriptive Statistics Simple counts: ogive

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

20. Symmetry

23. Right Left

25. 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

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

27. 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

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

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

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

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

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

33. Descriptive Statistics Central tendency: 3. Mean Harmonic

34. Descriptive Statistics Central tendency: 3. Mean Harmonic

35. Descriptive Statistics Central tendency: 3. Mean Harmonic

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

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

38. 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?

39. Problem: Customers do not perceive volume correctly.

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

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

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

43. 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.

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

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

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

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

48. 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.

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

50. 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.

51. 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

52. 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?

53. a.Give the central tendency measures of this sample.

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

55. 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.

56. 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?