Suppose case control study was conducted to assess the association between Khat

Suppose case control study was conducted to assess the association between Khat
chewing & cancer of oral mucosa. The findings are summarized in the table below.
Table: Data a case control study of Khat chewing and cancer of oral Mucosa. Number in the
bracket shows the smoking status of the individual
Khat Chewing Cancer of oral Mucosa
Yes No Total
Yes 552(121) 498(110) 1050
No 448(99) 1502(330) 1950
Total 1000 2000 3000
A. Calculate the odds of khat chewing among patients with cancers of oral
mucosa.
B. Calculate the odds of Khat chewing among those individuals free of cancer of
oral mucosa.
C. Calculate the crudes odds ratio and interpret the finding.
D. Calculate the attributable risk percent and interpret the Finding.
E. Is cigarette smoking a confounder for the association between Khat chewing
and Cancer of oral mucosa? Why?