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?