Review Contents of Business Statistics
- ANOVA:
- One-way ANOVA (randomized design),
- Two-way ANOVA with interaction
- ANOVA table
- Test for significance of Main effects Interaction effect
Example: Five stock analysts were asked to predict earnings for four different stocks for the next year. The following statistics summarize their responses:
N = 4*5 = 20
Source of Variation | Sum of Squares |
Between Analysts | 74.6 |
Between Stocks |
|
Error | 82.2 |
Total | 192.5 |
Build up the ANOVA table and test for the main effects
- Chi square Test for probability distributions
- Uniform distribution:
- Multinomial distribution:
- Test for independence of two qualitative variables
Example:
- In 2008, the student body of a state university in Utah consists of 30% freshmen, 25% sophomores, 27% juniors, and 18% seniors. A sample of 400 students taken from the 2009 student body showed that there are 138 freshmen, 88 sophomores, 94 juniors, and 80 seniors. Test with 5% significance level to determine whether the student body proportions have changed.
