Question

A contingency table, also called a two-way table, is made up of r rows and c columns. In general, how many cells are in a contingency table with r rows and c columns?

1) r x c (r times c)

2) (r-1)(c-1)

3) r + c

In general, how many degrees of freedom are associated with a contingency table with r rows and c columns?

1) r + c

2) r times c

3) (r-1)(c-1)

When should Fishers Exact Test be used instead of the usual chi-square test for a 2x2 contingency table?

a) if one or more of the cells has an observed frequency less than 5

b) n < 30

c) if one or more of the cells has an expected frequeny less than 5

d) np₀ < 5

There are two types of tests that can be performed using a contingency table. A test of independence and a test of

a) heterogeneity

b) Relationship

c) association

d) homogeneity

Answer 1

Q1. A contingency table, also called a two-way table, is made up of r rows and c columns. In general, how many cells are in a contingency table with r rows and c columns?

1) r x c (r times c)

In a contigency table the total number of cells is simply found by multiplying the number of rows with the number of columns.

Q2 In general, how many degrees of freedom are associated with a contingency table with r rows and c columns?

3) (r-1)(c-1)

The degrees of freedom is equal to (r-1)(c-1), where r is the number of rows and c is the number of columns.

Q3 When should Fishers Exact Test be used instead of the usual chi-square test for a 2x2 contingency table?

b) n < 30

If the sample size is small, we can use Fisher's exact test instead of the usual chi-square test.

Q4 There are two types of tests that can be performed using a contingency table. A test of independence and a test of

d) homogeneity

Contigency tables are also used for testing homogeneity.