Statistics Chapter 11 (Associations among categorical variables)

Question 1

In what table do you compare two categorical variables

Answer 1

In a contingency table

Question 2

What are conditional proportions and what does dependence mean

Answer 2

The proportion of the response variable for one level of the explanatory variable
The the explanatory variable affects the response variable they are associated and dependent

Question 3

What are the five steps for significance test for categorical variables (for independence or not)

Answer 3

1. Assumption
2. Hypothesis
3. Test statistic
4. P-value
5. Conclusion

Question 4

What are the 3 assumptions

Answer 4

1. Both variables are categorical
2. It is a random sample
3. Every cell has 5 samples

Question 5

In a significance test for categorical variables, what does H0 state

Answer 5

That the variables are independent

P(A and B) = P(A) * P(B)

Question 6

What does a high X^2 value state

Answer 6

It states that there is strong evidence against H0

It does not state that there is is strong associtation

Question 7

How do you measure the strength of an association

Answer 7

1. Difference in the relative risks (conditional proportions)
2. Ratio of relative risks (conditional proportions)

Question 8

When can you do a z test while comparing two categorical variables

Answer 8

Only if you have 2 columns and 2 rows

If more you have to do a X^2 test

Question 9

What is the difference between observed and expected frequencies In a significance test for categorical variables

Answer 9

observed is what you actually see and get as results

expected is the frequency you expect if H0 is true