# Thread: Help with a Probability question?

1. ## Help with a Probability question?

Hey anyone here good with Probability.

I used to know how to do this, but it has totally left my mind.

"John is collecting a set of 4 Native bird cards, from oatie flakes cereal packets.
The manufacturers of Oatie Flakes found that some of their machines malfunctioned and 20% of the packers of cereal contain 2 Native Bird cards."

1. Design a simulation to predict the number of packets that Oatie Flakes that are required to obtain a full set of Native Bird cards.
Describe the simulation in sufficient detail so that another person could repeat it without your help.

(What kind of simulation would this be done with to include the 20% malfunction?)

Heh... Damn I feel stupid. Lol.

2. You can simulate this in Microsoft Excel.
You must use the RAND() function in Excel. What this function does is that it tells Excel to randomly generate a number from the interval [0,1] with equal probability (in other words, a uniform distribution). Now for every random number that is less than or equal to 0.2, you can count that as a malfunction. For every random number that is greater than 0.2, you will count that as a box with all 4 cards included.

For example, if you run the RAND() 4 times and it happens to give:
0.213
0.123
0.532
0.234
Then you will have 1 malfunctioned box, and 3 normal boxes.

3. Originally Posted by Viesczy
Hey anyone here good with Probability.

I used to know how to do this, but it has totally left my mind.

"John is collecting a set of 4 Native bird cards, from oatie flakes cereal packets.
The manufacturers of Oatie Flakes found that some of their machines malfunctioned and 20% of the packers of cereal contain 2 Native Bird cards."

1. Design a simulation to predict the number of packets that Oatie Flakes that are required to obtain a full set of Native Bird cards.
Describe the simulation in sufficient detail so that another person could repeat it without your help.

(What kind of simulation would this be done with to include the 20% malfunction?)

Heh... Damn I feel stupid. Lol.
Monte-Carlo

RonL