Chi Squared Flashcards
1
Q
What is chi squared?
A
An non-parametric inferential statistical test
2
Q
What kind of data is involved?
A
Nominal data
3
Q
What does it measure?
A
Tests whether or not a pattern of observations is statistically significant
4
Q
How is degrees of freedom calculated?
A
n-1
5
Q
What are the main assumption?
A
- Nominal data
- More than 20 observations
- Cannot have 20% or more with exp. frequency <5
- No category with exp. frequency <1
- Frequencies, not percentages
6
Q
What is the procedure
A
- Hypotheses
- Determine confidence level
- Calculate X squared
- Calculate degrees of freedom
- Determine significance level
7
Q
What are observed values?
A
Frequency counts observed - one per category
8
Q
What are expected values?
A
Frequency counts expected if H0 were true
9
Q
If the sample represents the population what are we likely/unlikely to calculate?
A
Chi <1 is very likely
Chi >5 is very unlikely
10
Q
If X squared exceeds the critical value, what happens next?
A
Move forward with the alternative hypothesis
11
Q
Whats different about comparing samples?
A
- Degrees of freedom
- Expected values calculate for all categories in all samples
ei = (total row*total column)/Grand total
