Session 5 Topic: Sampling Theory/ Techniques and Discussions Project Brief ◦ Expectations and deliverables (Deadline October 1‚ 2010- EOD) Sampling basics ◦ Fundamental Issues ◦ Errors Sampling techniques ◦ Probabilistic ◦ Non-probabilistic Discussions © Krishanu Rakshit‚ IIM Calcutta 28 September‚ 2010 2 When do we use a ‘sample’ When do we use a census (population) Sampling errors ◦ Difference between a measure from sample and the measure
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Sampling Procedures There are many sampling procedures that have been developed to make sure that a sample really represents the target population. Simple Random Sampling In simple random sampling‚ every individual in the target population has an equal chance of being part of the sample. This requires two steps: 1. Obtain a complete list of the population. 2. Randomly select individuals from that list for the sample. In a study where the unit of analysis is the student‚ the researcher
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Concept and basics of probability sampling methods One of the most important issues in researches is selecting an appropriate sample. Among sampling methods‚ probability sample are of much importance since most statistical tests fit on to this type of sampling method. Representativeness and generalize-ability will be achieved well with probable samples from a population‚ although the matter of low feasibility of a probable sampling method or high cost‚ don’t allow us to use it and shift us to the
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Sampling Frame Advanced Cell technologies are constantly conducting hundreds of clinical trials in order to gain more knowledge on stem cell research. When dealing with the ethical barriers derived from stem cell research Advanced Cell Technologies spare no resources to maintain a healthy line so crossing of moral barriers occur. In order to conduct and proceed with research‚ a set of specific sampling frames must first be created. In statistics‚ a sampling frame is the source material or device
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The key is the use of statistically derived random sampling procedures. These ensure that survey results can be defended as statistically representative of the population. Surveys that do not follow these procedures can produce results that lead to misguided market research‚ strategic‚ or policy decisions. Any so-called "survey" in which no attempt is made to randomly select respondents‚ such as call-in readers’ or viewers’ "polls"‚ is likely to produce results that in no way reflect overall public
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Statistical Sampling Statistical Sampling 1. The authors of the paper make assumptions about the U.S. population on three dimensions. What are the three dimensions? (Hint: The authors refer to these dimensions as "components of change.") Answer: The three dimensions would be migration‚ fertility‚ and mortality. 2. What is the expected population of the U.S. in 2050 given the new series (i.e.‚ based on 1998 data) based on the lowest series? The middle series? And the highest
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Sampling plan Our target population is the youth‚ from ages of 16 to 23. They represent the young adults and teenagers of the area’s population and are the most easily influenced individuals of the society. Our target population are college and high school students or recently graduated high school students. The data collection method used will be a self-administered questionnaire handed to the prospective respondents and collected right after the 10 minutes needed for the individual to complete
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Population and Sampling MTH/231 August 29‚ 2012 Importance of Population and Sampling History from Political Arithmetic to Statistics The history timeline show evidence of statistical data as early as Ancient Greece time but records show statistics in late 16th century‚ when it was introduced by‚ John Graunt‚ William Petty‚ and Pascal and later in 17th century by Gottfried Achenwall. It was an exciting time when success and discoveries raised the confidence of scientists‚ physicist and astronomers
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Sampling Techniques Worksheet For each description of sampling‚ decide if the sampling technique is A. Simple Random B. Stratified C. Cluster D. Systematic E. Convenience 1. In order to estimate the percentage of defects in a recent manufacturing batch‚ a quality control manager at Intel selected every 8th chip that comes off the assembly line starting with the 3rd‚ until she obtains a sample of 140 chips. 2. In order to determine the average IQ of ninth-grade students‚ a school psychologist
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Sampling is concerned with the selection of a subset of individuals from within a statistical population to estimate characteristics of the whole population. Acceptance sampling is used to determine if a production lot of material meets the governing specifications. Two advantages of sampling are that the cost is lower and data collection is faster than measuring the entire population. Sampling is the process of selecting units (e.g.‚ people‚ organizations) from a population of interest so that
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