# Easy probability question help?

1. Sep 24, 2011

### Shekster

Easy probability question help??

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Above are the trading volumes (millions of shares) for stocks traded on the NYSE during a certain period.
Assume that the probability distribution of the trading volumes is approximately normal.

2.2 What is the probability that on a particular day the trading volume will be less than 800 million shares?

2.3 What is the probability that on a particular day the trading volume will exceed 1 billion shares?

2.4 If the exchange wants to issue a press release on the top 5% of trading days, what volume will trigger a press release??

This is not homework i am trying to explain this to my brother and don't know how too, answers with working out would be required.

2. Sep 24, 2011

### Bacle

Re: Easy probability question help??

With the context you gave, this just seems like an issue with the sampling distribution

of the mean, which follows from the central limit theorem. Look up those terms and let

us know of any followup question. The sampling distribution is just that; a distribution

which allows us to determine the probabilities of events.