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Cards In This Set
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Sampling is a
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Tool to infer something about a population based on a sample.
determine population parameter based upon the sample |
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A sample is a part of
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Population of interest
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We construct a distribution of the _____ to understand how
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Sample mean to understand how the sample means tend to cluster around the pop mean
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We do all this to show that the population shape
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Of the sampling distribution tends to follow the normal probability distribution
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Sampling is based on _______ statistics
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Inferiential: which is to find something about a population based on a sample
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A sample is
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A portion or part of the population of interest
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5 reasons to sample:
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1. contacting the whole pop would be time consuming
2. the cost of studying all the items in a pop may be prohibitive 3. physical impossibility of checking all items in the pop 4. destructive nature of some tests 5. sample results are adequte |
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Simple random sample
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Most widely used
a sample selected so that each item or person in the pop has the SAME CHANCE OF BEING INCLUDED |
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Table of random numbers
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Numbers have been generated from a random process, probablity is the same for each number
bias is eliminated from selection process |
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Systematic random sampling
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A random starting point is selected and then every kth member of the pop is selected
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Who is k calculated?
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Population size/ sample size
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The systematic random sampling method should not be used when:
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When the physical order is related tto the population characteristic
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Stratified random sampling
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Pop can be clearly divided into groups based on some characteristic
each group is represented in the sample |
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What are the groups called?
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Strata
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Simple random sampling is used once strum are created
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True
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