given data table is
|
group 1 |
group 2 |
| yes |
711 |
263 |
| no |
1159 |
313 |
calculating row and column total or sum
|
|
group 1 |
group 2 |
TOTAL |
|
yes |
711 |
263 |
974 |
|
no |
1159 |
313 |
1472 |
|
TOTAL |
1870 |
576 |
2446 |
For expected count, take sum of each row and column
then multiply the row and column total for individual value and
divide by the grand total, we get
|
Table for expected count |
group 1 |
group 2 |
|
yes |
(1870*974)/2446 = 744.636 |
(576*974)/2446 = 229.364 |
|
no |
(1870*1472)/2446 = 1125.364 |
(576*1472)/2446 = 346.636 |
Contribution to chi square is calculated (observed -
expected)^2/(expected)
|
Observed |
Expected |
Contribution |
|
711 |
744.636 |
(711-744.636)^2/744.636 = 1.519 |
|
263 |
229.364 |
(263-229.364)^2/229.364 = 4.933 |
|
1159 |
1125.364 |
(1159-1125.364)^2/1125.364 = 1.005 |
|
313 |
346.636 |
(313-346.636)^2/346.636 = 3.264 |
Chi square = 1.519 + 4.933 + 1.005 + 3.264
= 10.721
