Detailed Answer
Correct answer: (D)
A simulation is like a lottery, where there are (in this case) 100 little balls, each with a number on it.
The computer reaches in and pulls out one ball at a time and records the result. This process is used to create
a forecast of what any given day’s demand will actually be, based upon the given probabilities. One ball is
pulled out for each day. If there are 100 balls, 10 of them (10%) represent a daily demand of zero, 15 of
them (15%) represent a demand of 1, and so forth. Theoretically, then, the computer has a 10% chance of
pulling out a ball representing demand of zero, a 15% chance of pulling out a ball representing demand of 1,
and so forth, each time it reaches in.
Here, the person running the simulation has determined that 10% of the balls should represent a daily
demand of zero; 15% of the balls should represent a daily demand of 1, and so forth. This question is asking
what the numbers should be on the balls that will represent a daily demand of 4 and a daily demand of 5,
assuming that there will be 100 balls and they will be numbered consecutively from 0 through 99. We are
given the numbers to be assigned to balls 00 through 64, representing daily demand of 0 through 3.
First, count how many balls are in each of the intervals that are given. For daily demand of 0, there are 10
balls, numbered 00 through 09. (To calculate the number of balls, subtract the smaller ball number from the
larger ball number and add 1.) For a daily demand of 1, there are 15 balls, numbered 10 through 24. And so
on.
When you have finished this, you will see that the number of balls in each interval is the same as the
probability for each daily demand level. So now you know how many balls need to be in the group
representing daily demand of 4 heaters and how many in the group representing 5 heaters. The numbers will
be the same as the probability for each demand level. And that makes sense, because there are to be 100
balls. So the number of balls in each level should be the same as the probability.
A simulation is like a lottery, where there are (in this case) 100 little balls, each with a number on it.
The computer reaches in and pulls out one ball at a time and records the result. This process is used to create
a forecast of what any given day’s demand will actually be, based upon the given probabilities. One ball is
pulled out for each day. If there are 100 balls, 10 of them (10%) represent a daily demand of zero, 15 of
them (15%) represent a demand of 1, and so forth. Theoretically, then, the computer has a 10% chance of
pulling out a ball representing demand of zero, a 15% chance of pulling out a ball representing demand of 1,
and so forth, each time it reaches in.
Here, the person running the simulation has determined that 10% of the balls should represent a daily
demand of zero; 15% of the balls should represent a daily demand of 1, and so forth. This question is asking
what the numbers should be on the balls that will represent a daily demand of 4 and a daily demand of 5,
assuming that there will be 100 balls and they will be numbered consecutively from 0 through 99. We are
given the numbers to be assigned to balls 00 through 64, representing daily demand of 0 through 3.
First, count how many balls are in each of the intervals that are given. For daily demand of 0, there are 10
balls, numbered 00 through 09. (To calculate the number of balls, subtract the smaller ball number from the
larger ball number and add 1.) For a daily demand of 1, there are 15 balls, numbered 10 through 24. And so
on.
When you have finished this, you will see that the number of balls in each interval is the same as the
probability for each daily demand level. So now you know how many balls need to be in the group
representing daily demand of 4 heaters and how many in the group representing 5 heaters. The numbers will
be the same as the probability for each demand level. And that makes sense, because there are to be 100
balls. So the number of balls in each level should be the same as the probability.
