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Lesson 1- COMM 215 Fall13-TeacherPost

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Unformatted text preview: ___________ scale of measurement.   Cross ­Sectional Data ­ same point in time   Today, I will be collecting data from all COMM 215 students at the same time.   Time series data ­ diﬀerent times   Through out the semester, I will be collecting data every week from a few speciﬁc students.   Existing Sources   Statistics Canada (www.statcan.gc.ca)   Data Acquisition Errors             Making errors during data collection Writing 24 ­year ­old as 42 year ­old Asking ambiguous questions Inconsistency Spotting outliers Selection bias   Descriptive Statistics utilizes numerical graphical methods   to look for patterns in a data set   to summarize the information revealed in a data set   to present the information in a convenient form.   Inferential Statistics utilizes sample data   to make estimates, decisions, predictions, or other generalizations about a larger set of data. Sample of 500 Students in COMM215 Year COMM215 Failure Rate 2009 12.7% 2010 12.3% 2011 12.1% 2012 ???? Cola wars is the popular term for the intense competition between Coca ­Cola and Pepsi displayed in their marketing campaigns. Their campaigns have featured movie and television stars, rock videos, athletic endorsements, and claims of consumer preferences based on taste tests. Suppose, as part of a Pepsi marketing campaign, 1,000 cola consumers are given a blind taste test. Each consumer is asked to state a preference for brand A or brand B.   Describe the population.   Describe the variable of interest.   Describe the sample.   Describe the inference.   Population of interest: all cola consumers   Variable of interest: cola preference   Sample: 1,000 cola consumers selected   Inference: generalization of the cola preference of 1,000 sampled consumers to the population of all cola consumers.   Statistical thinking   Know how the data was collected ­ Is the data from a reliable source?   Is it a random sample? Or “Self ­Selected”?   Is it possible? Does the data make sense?   If the biased sample was intentional, with the sole purpose to mislead the public the researchers would be guilty of unethical statistical practice.   “ Research Study Reveals…” As a statistics student who wishes to avoid accepting biased results, what single question should be foremost in your mind as you begin reading the article?   You should ask yourself what beneﬁts the person or company stands to gain from the conclusions reached by the study.   Forensic DNA Databases and Race: Issues, Abuses and Ac...
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