Proportion comparaison between 4 modalities of one factor in R (chi2?) I would need help in order to perform a proportion comparison between 4 different modalities of one factor.
Here is an example.
I would like to compare the proportion of mother-to-child smoking between individuals from 4 different countries.
Contry   USA  INDIA  CHINA  ITALIA
Mother   100  2000   1600   200 
Child    25   860    64     10
%        25%  43%    4%     5%    

So what I would like to compare is then the percentage of smoking child between countries
I firts tought to chi2 test of fit to a uniform distribution law such as:
           USA  INDIA  CHINA  ITALIA  
observed   25%  43%    4%     5%    
expected   25%  25%    25%    25% 

But I know chi2 does work only on numbers and not on proportions, right ?
Does someone have an idea of a test to support that USA and INDIA have a significantly higher level of smoking childs regarding their mothers compared to CHINA and ITALIA compared to what is expected if it were homogeneous ?
Thanks a lot for you help and time
Note: keep in mind that it is just a toy data, meaningless without any biological sens, I just want to put a sample example where I would like to compare proportions.

A 4-sample proportion test. The null being prop.test can be used for testing the null that the proportions (probabilities of success) in several groups are the same, or that they equal certain given values.
> prop.test(c(25,860,64,10),c(100,2000,1600,200))

    4-sample test for equality of proportions without continuity correction

data:  c(25, 860, 64, 10) out of c(100, 2000, 1600, 200)
X-squared = 772.76, df = 3, p-value < 2.2e-16
alternative hypothesis: two.sided
sample estimates:
prop 1 prop 2 prop 3 prop 4 
  0.25   0.43   0.04   0.05

resulting in a rejection of the null (unsurprisingly).
