Scaling API-first – The story of a global engineering organization
Basic Stat Notes
1. Graphs, Charts, and Tables – Describing Your Data Business Statistics Dr.M.Raghunadh Acharya 06/08/09
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9. Frequency Distribution Example Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 Class Frequency 10 but under 20 3 .15 20 but under 30 6 .30 30 but under 40 5 .25 40 but under 50 4 .20 50 but under 60 2 .10 Total 20 1.00 Relative Frequency Frequency Distribution 06/08/09
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11. Histogram Example Class Midpoints Data in ordered array: 12, 13, 17, 21, 24, 24, 26, 27, 27, 30, 32, 35, 37, 38, 41, 43, 44, 46, 53, 58 No gaps between bars, since continuous data 06/08/09
24. Pie Chart Example Percentages are rounded to the nearest percent Current Investment Portfolio Savings 15% CD 14% Bonds 29% Stocks 42% Investment Amount Percentage Type (in thousands $) Stocks 46.5 42.27 Bonds 32.0 29.09 CD 15.5 14.09 Savings 16.0 14.55 Total 110 100 (Variables are Qualitative) 06/08/09
33. Scatter Diagram Example 06/08/09 Volume per day Cost per day 23 125 26 140 29 146 33 160 38 167 42 170 50 188 55 195 60 200
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39. Center and Location Mean Median Mode Other Measures of Location Weighted Mean Describing Data Numerically Variation Variance Standard Deviation Coefficient of Variation Range Percentiles Inter quartile Range Quartiles Summary Measures 06/08/09
40. Center and Location Mean Median Mode Weighted Mean Overview: Measures of Center and Location 06/08/09
57. Variation Variance Standard Deviation Coefficient of Variation Population Variance Sample Variance Population Standard Deviation Sample Standard Deviation Range Interquartile Range Measures of Variation 06/08/09
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62. Median (Q2) X maximum X minimum Q1 Q3 Example : 25% 25% 25% 25% 12 30 45 57 70 Interquartile range = 57 – 30 = 27 Interquartile Range 06/08/09
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65. Sample Data (X i ) : 10 12 14 15 17 18 18 24 n = 8 Mean = x = 16 Calculation Example: Sample Standard Deviation 06/08/09
66. Mean = 15.5 s = 3.338 11 12 13 14 15 16 17 18 19 20 21 11 12 13 14 15 16 17 18 19 20 21 Data B Data A Mean = 15.5 s = .9258 11 12 13 14 15 16 17 18 19 20 21 Mean = 15.5 s = 4.57 Data C Comparing Standard Deviations 06/08/09