QMS 102 Chapter Notes - Chapter 8: Simple Random Sample, Sampling Distribution, Royal Institute Of Technology
2 Jan 2018
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Selecting a sample is less time consuming and less costly. Frame - a listing of items that make up the population (data sources) Inaccurate results if a frame excludes certain portions of population. Non-probability sample - you select items or individuals without knowing their probabilities of selection: convenience sampling - items selected are inexpensive or convenient to sample. Judgment sampling - get the opinions of preselected experts in the subject matter (cid:523)can"t generalize their results to general public(cid:524: convenient, speed, low cost. Probability sample - select the items based on known probabilities: simple random sample - every item from a frame has the same chance of selection as every other item. Randomly select one item from 1st group, select every kth individual thereafter: less efficient, stratified sample - subdivide the n items in the frame into separate subpopulations (strata) (dividing into groups of common characteristic - m/f.
