initiate gp1, g1, gp2, g2      //The number of positive cases in Group1, Group1 total cases, positive cases in Group2, Group2 total cases.
average = (gp1+gp2)/(g1+g2)
flag = gp1/g1 - gp2/g2

if(flag >= 0){
  joint1 = BINOM.DIST(gp1-1;g1;average)          // Left-side binomial disribution
  joint2 = 1 - BINOM.DIST(gp2;g2;average)        // Right-side binomial disribution
} else {
  joint1 = 1 - BINOM.DIST(gp1;g1;average)
  joint2 = BINOM.DIST(gp2-1;g2;average)  
}
joint = joint1 * joint2
ebt_p = 1 - joint