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Week one Visual Displays: Histogram Census v. Sample Statistic v. Parameter Descriptive Statistics Center : Mean Median Mode Dispersion: Range, Interquartile Range Standard Deviation (Variance) Chebyshev’s Theorem Skewness Standardized Values Review and practice of week one material. Sellit INC is considering changing its pay scale. They feel that individuals with families work harder are less subject to attrition and deserve more pay. On average each of a firm’s employees sells $3500 per week. The per employee weekly sales variation is approximately $500. Median Sales are $3,200. To test the theory, the company randomly samples several of its employees with families getting the following results: emp sales 1 6000 2 5000 3 4000 4 6000 5 4000 6 4000 7 1000 8 2000 9 6000 10 2000 Compare and contrast the employees with families to all employees. Are employees with families better? Week two Marginal, joint and conditional probability P(A or B) = P(A) +P(B) – P(A and B) P(A|B) = P(A and B)/ P(B) mutually exclusive Independence M&M exercise 1. determine the probability of each color 2. determine P(color and Kind) 3. determine P(color | kind) 4. determine P(kind | color) 5. explain the difference between 2,3 and 4. 6. are color and kind independent? 7. give and example of mutual exclusion. 8. Develop a contingency table for color and kind. Practice problems: 1. Twenty percent of cars end up in the junkyard within 4 years of manufacture. Eighty percent of the cars that end up in the junkyard within 4 years are there because of an accident. Wiper motors invariably survive accidents and can be recycled. What percentage of cars will have junkyard recyclable wiper motors within 4 years of manufacture? 2. When a car is in an accident, the front end is damaged 10 percent of the time. The rear end is damaged 5 percent of the time, and one percent have both ends damaged. Is rear end damage independent of frontend damage? What percentage have damage at at least one end?