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# Statistic question I need direction watch

1. Weekly demand for packs of a certain make of chocolate trifle at a major supermarket store has a Normal distribution with mean of 200 and standard deviation of 40 packs.

(a) What would be the probability that the store sells out of trifles by the end of a week if it restocks its fridge with chocolate trifles up to a stock level of 280 packs at the start of each week?

(b) Any unsold trifles need to be thrown away at the end of the week. Estimate the weekly wastage.

For (a) I got p(z=2)=0.0275
But I don't know how I should do (b) could anyone give a hint please.

Thank you
2. (Original post by Sig)
For (a) I got p(z=2)=0.0275
But I don't know how I should do (b) could anyone give a hint please.

Thank you
You mean P(z>2) ?

Check your subtraction 1 - 0.9772 =

As for part b,

What's the mean demand? How many do they stock? How many will be wasted on average?
3. (Original post by rnd)
You mean P(z>2) ?

Check your subtraction 1 - 0.9772 =

As for part b,

What's the mean demand? How many do they stock? How many will be wasted on average?
Yeah P(z>2)= .02275

So mean Demand 200, they stock 280, 80 will be wasted on avarage, is this corect? (seems too easy, thus I am suspisioss)

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