9.4 inferences for 2-way count data

Question 1

What is the notation for each cell?

Answer 1

n_ij

i = row
j = column

Question 2

What is the notation for column total for row 1?

Answer 2

n_1•

Question 3

What is the notation for row total for column 1?

Answer 3

n_•1

Question 4

What is the chi-square for a test of independence for the two discrete variables X and Y?

Answer 4

Sum of all (n_ij - E_ij)^2 / E_ij

e.g. the things you add for chi-square are all the cells.

Question 5

How do you find E_ij?

e.g. the expected frequencies for each cell

Answer 5

Row total * column total / overall total

Totals are for the rows/columns corresponding to that cell