Module 9: Chi-squared test

Question 1

One way expected contingency tables use

Answer 1

-whether there are differences among counts of that categorical variable

Question 2

One way expected null and alternative

Answer 2

-Ho: no difference in allergy type among children
-Ha: there is a difference

Question 3

Two way expected contingency tables use

Answer 3

-whether the counts across levels of one variable change differently depending on what level of the other variable is being looked at

Question 4

Two way expected null and alternative

Answer 4

-Ho: type of allergy and home heating source are independent
-Ha: these are not independent

Question 5

How to calculate expected tables

Answer 5

-one way: add all up and divide by number of cells
-two way: find marginal distributions for rows and columns and then find the total and multiply by distribution of both row and column

Question 6

Chi-squared use

Answer 6

-measures distance between observed and expected contingency tables

Question 7

Chi squared null distribution shape

Answer 7

-bell curve shifted to left side because it can only have positive values

Question 8

Chi squared degrees of freedom

Answer 8

-one way table: k-1
-two way table: (c-1)(r-1)
-k is for number of cells
-c is for number of columns
-r is for number of rows

Question 9

Chi squared reporting

Answer 9

-symbol for test (x2)
-degrees of freedom
-total count of observed table
-observed chi squared value (2 decimal places)
-p value (5 decimal places)