Random Sampling question - taking samples from the same spot!

S

selena15

#1
Hi Cove
all time :(
I Got a question
in the plant, i was observing one lady to making one check of goods, based on random sampling. but during the check, i've remarked that she took all the time the items from the same place of the package!
asking here : what she was doing? She is expected to take the sample with a random approch, even she is making the first hold of the packages with the random approch, she said that she is taking the item from the package from the same place into it and asked her coleagues to do the same (they make a deal:mg:) like this the increasing the possibility to get the possible NC goods!!!
I'm confused little bitte.
if the box of goods package contain about 10 items of goods and each one contain more than 10 final goods. but my query, if she is taking the requested quantity of package from the same place into the box, does this mean that she's biasing the check or no ?
 
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Jim Wynne

Staff member
Admin
#2
Re: random sampling

In this sense, "random" means that every member of the population has an equal chance of being selected each time a sample is drawn. If that's not the case in your situation, it's not random sampling that's being done. If you're using a statistically-based sampling plan, random sampling is assumed, and if the sampling isn't random the plan won't be reliable.
 
L

LEDgible-man

#4
I would have to add, it also depends on how the box is populated...

I.e. is the box filled sequentially, piece by piece in an orderly fashion. Let me rephrase, the possibility of random probability could be left for a section further up the assembly line such as when there is a forced bottleneck on an assembly line.

If the entire line is producing piece by piece products (single line) then the random probability is in the workers hands (such as choosing randomly in the box). If the conveyor produces many products (such as a soda can factory that bottlenecks the line to stamp then re-expands to eventually re-bottleneck to package) I think (not sure) randomization is conserved.

line 1
ooooooooooooooooooooooo

line 2
ooooooooo___________ooooooooooo
ooooooooooooooooooooooooooooooooooooooooooo
ooooooooo___________ooooooooooo

I hope that clarifies. I could be missing something in concept.
 
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