STAT 210: Chapters 1 and 2
20 Cards in this Set
Front | Back |
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Population
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entire group of individuals about which the researcher wants information
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Parameter
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characteristics of a population that the researcher wants to measure, GREEK LETTERS, proportion, average, mean
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Sample
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a subset of the population that is contacted and examined for research
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Statistic
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descriptive measure computed from data in a sample that can be expressed or evaluated numerically
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Inference
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statement about a population based on data collected in a sample
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Distribution
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listing of values that a characteristic can take and the number or percentage of times each value occurs
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Descriptive statistics
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branch of stat which use data and statistics computed from a sample
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Replication/repetition
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Repeated measurements
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Constant
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measurements that do NOT change in repeated trials over time
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Variable
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measurements vary and change in trials over time
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Discrete quantitative variables
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Things you can count
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Continuous quantitative variable
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anything that is measured or calculated, averages, rates, percentages
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Selection bias
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one or more types of subjects are systematically excluded from the sample
Ex: Raising fees to expand the Siegal center and only asking students at the game (creates a bias)
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Non response bias
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individual from the sample can not be contacted or refuses to respond
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Response bias
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responders give inaccurate information or if they interviewer influences the subject to respond in a certain way.
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Haphazard sample
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selecting a sample by using some kind of convenient mechanism/technique that does not involve randomization.
Ex: Standing outside Cabell at 3:00 to ask about classes beginning at 2:30
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Volunteer response samples
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subject volunteers to be part of the study. Call in survey, internet, etc. Bias because most responders are going to feel either very strongly on their opinion either pos or neg
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Simple random sampling
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list of all possible individuals in a population and randomly choose "n" subjects. Every person has an equal chance at winning. Refer to the table of random digits after assigning every subject a number.
+Easy, random
-Sample may contain too large of a percentage of a subject (M or F)
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Stratified random sampling
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population is naturally divided in to two or more groups of similar subjects called strata. EVERY GROUP HAS AT LEAST 1 SELECTED.
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Multistage random sampling
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population- all American college students population naturally divided in to 2 groups, randomly select several of these groups, each chosed group is further divided in to smaller subgroups, simple random sampling is used to pick from subgroups
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