calculate chi square and risk across observations

dlsfetcu — Sun, 27 Jan 2013 08:32:48 GMT

Very grateful for any help with this basic question

Historical data used to research the question of whether smoking causes cancer

yields the following table.

Smoking Habit/Cancer Cancer No Cancer Total

None to Slight 56 956 1012

Moderate to Excessive 269 1646 1915

Total 325 2602 2927

Question:

1) calculate the risk of a person who is a moderate

or excessive smoker having cancer?

2) perform a chi - square test on these data using

PROC FREQ and state your conclusions?

MY answer for 2)

data nothing;

input Smoking_Habit_Cancer $ 1-22 Cancer 23-26 No_Cancer 27-31 Total 32-36;

datalines;

None to Slight 56 956 1012

Moderate to Excessive 269 1646 1915

Total 325 2602 2927

;

ods html;

PROC FREQ ORDER=DATA; WEIGHT cancer ;

TABLES smoking_habit_cancer*cancer /chisq ;

RUN;

ods html close;

Re: calculate chi square and risk across observations

Reeza — Sun, 27 Jan 2013 19:33:41 GMT

That looks like homework to me, but I'll tell you its wrong. Take a look at your proc freq output, the table should at least match your input table, if it doesn't you haven't done your chi-square correctly.

See the example in the docs that does pretty much what you're looking for:

Base SAS(R) 9.2 Procedures Guide: Statistical Procedures, Third Edition

topic calculate chi square and risk across observations in SAS Procedures

calculate chi square and risk across observations

Re: calculate chi square and risk across observations