The table below contains counts of mouth cancer for smokers

The table below contains counts of mouth cancer for smokers and non smokers from a medical center.

Cancer?

Yes

No

459

11

470

9

321

330

Estimate the standard error for the difference in proportions of those who had cancer (YES) (psmokers pnon-smokers)?

Calculate a 95% Confidence Interval for the difference in proportions

Assume that a 95% Confidence Interval for a difference in two proportions was (-.25, .15). Based on these results, can we say that there is a statistically significant difference between these two proportions?

Solution