 Our newsboy was only able to give us a little bit less accurate historical data. It was very coarse. The table gives us a set of discrete values, 3,000, 3,500, 4,000 for the demand, increasing up to 5,500, and then he gave us the probabilities for each one of those discrete values, 10, 15, 20, and so forth. The method we need to use to get our random variable requires us to use something called a lookup function. And the lookup function requires that we have our data range like I have it here with the information, the variable of interest, the demand, and a column adjacent to an empty column. And in this empty column, which I've labeled lookup column, we need to have the cumulative probabilities. By having the cumulative there, we can use the ran function to give us a probability to lookup, and the lookup function will jump into this column, start looking for a probability. If it hits one that is bigger than it is, it drops back and gives us that value of demand. To complete the lookup table, we need to have the cumulative probabilities from this column here. So we need to use the sum function. Clicking that cell equal SUM to insert the function, and we're going to start with that first probability, make it into a range. Now I want to unlock that first cell using the F4 key so I can drag this down. And as I grab that corner, I can drag that formula down to get our cumulative probabilities. If I click on this last one, you can see that the range has expanded as we drove down, which is what we wanted. Now we can use the lookup function to give us our randomized value for demand. I'm going to click in this cell here, and we're going to click in equal, lookup, and that's just the basic lookup function. And we want to lookup a value, which is going to be our random function, in case a probability, but a comma, and then we need to get the array, and that's going to be that array there. Close it and enter it. And so now we've got our first lookup value of 4500. And you can see as I cycle the sheet that the lookup function will take whatever random value that is, look it up and return the demand. So up here on our demand, again, I've used that max function in round as well in order to make sure that we get a reasonable value for our demand.