A study of Hodgkins disease classified n 538 patients by hi

A study of Hodgkin?s disease classified n = 538 patients by histological type (LP = lymphocyte predominance, NS = nodular sclerosis, MC = mixed cellularity, LD = lymphocyte depletion) and response to treatment (positive, partial, none), resulting in the following 4 x 3 contingency table:9 Do these data provide evidence that response to treatment for Hodgkin?s disease varies by histological type?

Solution

Let us do chi square test to check whether disease depends on histological type.

H0: Response to treatment is not dependent on histological type.

Ha: Atleast two responses are associated

Two tailed chi square test

The chi square statistic = 75.8901

df = 2x3 =6

p value = 0.0000 <0.00001

Hence the result is significant.

There is association between treatment and histological type

Results
	Category 1	Category 2	3			Row Totals
Group 1	74  (60.70)  [2.91]	18  (18.94)  [0.05]	12  (24.36)  [6.27]			104
Group 2	68  (56.03)  [2.56]	16  (17.49)  [0.13]	12  (22.48)  [4.89]			96
3	154  (155.25)  [0.01]	54  (48.45)  [0.63]	58  (62.30)  [0.30]			266
4	18  (42.02)  [13.73]	10  (13.12)  [0.74]	44  (16.86)  [43.67]			72
Column Totals	314	98	126			538  (Grand Total)