I am in my first year of biomedical sciences and i currently am trying to write a paper about the difference in the incidence of a specific infectious disease between men and women.

I am using an available dataset with the data about the incidence of the disease in a specific country. I tried doing the two-sample z-test to compare the proportions of males and females and i ended up with a p-value of 0 in excel. (by increasing the number of decimal places, it is still infinitely 0 - the scientific notation even says that p value is 0,00E+00.

I am using the two sample z-test formula for porportions which we have learned so far:

p1-p2/sqrt((p*(1-p)*(1/n1 + 1/n2))

Therefore, i was wondering if i am doing something wrong. My thought process is the following:

1) i have the total number of females in the country (both infected+not infected) - n1 ; i have the total number of males in the country (infected+not infected)- n2.

2) for the p1 i divide the total number of infected females with the total number of females in the country; for the p2 i divide the total number of infected males with the total number males in the country.

3) the p in my formula is then all the infected people divided by the total population of the country

I follow the formula and then excel gives me a p-value of 0.

Am i doing something wrong or if i am correct, how is the correct way to write about it in my paper?

Thank you!