From the point one on the graph, you go up (rise) making loops each time you go up (shown in red) then, once you've reached the same hight of point two, you go over (run), making loops once again (shown in blue). Then, you take the rise and put it over the run, so in the image attached it would be 4/3.
you look at the distance between the 2 points by looking at how many points its goes up or down, and you look at how points it goes from the left to the right or vice versa. but if you don't have a graph to look at, you will want to use the slope formula. look up the slope formula and plug it in.
Since the data is insufficient. Let us denote that n1 = 100, n2 = 100X1 = 38. X2 = 40 So looking for the p value: p = (38+ 40) / (100 + 100) = 0.39 z = (38/100 - 40/100)/√ (0.39*(1-0.39)*(1/100 + 1/100))= -0.2899 P-value = P (|z| > 0.2899) = 0.7718
