1. 11.1: Tests for Goodness of Fit
By the end of class you will be able to use the chi square test to check for the goodness of fit between a sample and population.

2. Chi Square Distribution?

3. Some Uses for Chi Square
Test for goodness of fit (if a frequency distribution matches a known distribution)
Tests for independence of variables (are results based on two different populations)
Tests for homogenity (does the entire population “behave” the same way)
**All tests will be right tail**

4. You are buying a new car! What color do you want?
White
Black
Silver
Blue
Gray
Red
Beige/Brown
Green/Yellow
20%
17%
13%
12%
11% 5%

6. You ar What color do you want? Expected Values:
White
Black
Silver
Blue
Gray
Red
Beige/Brown
Green/Yellow
20%
17%
13%
12%
11% 5%

7. Chi Squared Goodness of Fit
Degrees of Freedom: _________________
Test Value:
Ho: There is no difference between the observed values and expected values
H1: Our sample shows a preference (difference)

8. M&M’s: Are the colors really distributed as the Mars company predicts at .05?

9. Ambulance Calls (.1): Mt. Laurel EMS calls represent those of NJ.
Claims (NJ):
Saturday: 20%
Sunday: 10%
Monday:8%
Tuesday: 7%
Wednesday: 15%
Thursday: 20%
Friday: 20%
Actual out of 147 (mtl)
Saturday: 29
Sunday: 11
Monday: 13
Tuesday: 9
Wednesday: 25
Thursday: 29
Friday: 31

10. A teacher made a multiple choice test with the following distribution of answers. Is the distribution of answers what one would expect at a .05 level of significance? A: 10 B: 6 C: 2 D: 2

11. Summarizer: Rate it On a scale from 1-5, how well are you able to accomplish today’s mastery objective? Explain.