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sampling

Debate and discussion of any biological questions not pertaining to a particular topic.

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sampling

Postby michimichi » Thu May 24, 2012 3:36 am

hi, can anyone help me,
how can many samples should i take in order to have a representative sample of 500 items/samples?
can u also give me a formula?
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Postby michimichi » Thu May 24, 2012 4:06 am

edit,
how many samples should i take in order to have a representative sample of 500 samples/items? im using a random sampling
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Postby JorgeLobo » Fri May 25, 2012 10:25 am

Can;t answer without understanding the test objective (your sampling for purpose - not just for the sake of getting samples) and dynamics invovled. Can you be more explicit?
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Re: urgent!

Postby JorgeLobo » Sun May 27, 2012 10:54 am

Sorry michi - there really is no pat answer. Factors such athe anticipated importance, frequency and distribution of the character you expect to measure/detect will dictate the statistical confidence your sampling.
There would be differences, for example, between sterility testing of a injectble drug product and analysis of water samples from a city.
Can you tell us what you are trying to find or measure and it's nature?
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Postby michimichi » Mon May 28, 2012 6:46 am

i have 500 packs of tuna in one container van, i only need 1 pack to be delivered to the lab for chemical and micro analysis.
.The pack that i will transfer should be a composite sample from the 500 packs in the van.so how many packs should i be getting in order to get 1.?
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Postby JorgeLobo » Mon May 28, 2012 11:44 am

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Postby JorgeLobo » Wed May 30, 2012 9:16 pm

michi - did this help?
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Postby michimichi » Fri Jun 01, 2012 2:14 am

ya, thanks
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