Do you have a TI-84 Plus? Let's do the second one first, as it's more straightforward. 2nd vars Scroll down to B:binomcdf enter binomcdf trials:14 p:0.55 x value:3 Paste [The reason for 3 in x-value is because the calculator understands 3 as "3 or less", which is the same as "fewer than 4". Scroll to Paste enter you see binomcdf(14,0.55,3) enter 0.011430528 ----------------- The first one: You will have to first calculate the probability of the complement event, then subtract from 1. The complement of " at least 3 " is " 2 or fewer " 2nd vars Scroll down to B:binomcdf enter binomcdf trials:14 p:0.55 x value:2 Paste [The reason for 2 in x-value is because the calculator understands 2 as "2 or less" Scroll to Paste enter you see binomcdf(14,0.55,3) enter 0.002150974 But that's not the answer. You must subtract from 1. 1 - 0.002150974 0.997849026 Round to 4 decimal places. Edwin