# What is the probability of

reefland
I have a building with 2,000,000 items in it. Of those 2,000,000 items about 15,000 are shipped everyday. There are locations in the building which contain 35,400 items, 1,062 cannot be reached. How do I determine the probability of these 1,062 items being needed (assuming all 2,000,000 items are needed equally) in a day/month/year?

Homework Helper
I don't understand this:
"There are locations in the building which contain 35,400 items, 1,062 cannot be reached."

I could understand if it were just that 1062 of the 2,000,000 items could not be reached but what does "there are locations in the building which contain 35,400 items" mean?

reefland
Of the 2,000,000 items in the building, there are 35,400 items stored in locations that may become inaccessible (items falling to the floor, etc.) and through random sampling of these locations, it was determined the 1,062 (or 3%) of these 35,400 fall to the floor.

Just to clarify further, of the 2,000,000 items, 35,400 of them are stored in locations and have the potential to become inaccessible. Our current sample shows that 1,062 of them are in fact inaccessible. I think we are looking for N of A Given B:
B = based on 15,000 items picked per day, how many of them will be in the 35,400
A = based on B, how many of these items will be of the 1,062 that are inaccessible.

Rogerio
reefland said:
B = based on 15,000 items picked per day, how many of them will be in the 35,400
A = based on B, how many of these items will be of the 1,062 that are inaccessible.

15,000 * 35,400 / 2,000,000 = 265.5

So, 265.5 items will be in the 35,400

And about 8 (3%) will be inaccessible.