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33 Cards in this Set
- Front
- Back
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Sampling with replacement
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A number is not removed from the population because it has occured
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Stratified Sampling
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Classes or strata are formed inside a population. A simplee random sample is than drawn from each class or strata
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Systematic sampling
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Every nth element of a population is chosen (like every 12th person)
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Cluster sampling
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Populations are divided into areas. Areas are than selected at random and every element of the area is tested
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Convenience Sampling
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Elements chosen by how handy they happen to be
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Census
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Count everyone or everything
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Survey
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Ask a sample to gather data
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Problems with surveys
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the sample may be biased, self-selected, or may contain a hidden bias, which is unknown to the surveyor and even the population. you may miss variables when asking your question
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Statistics
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Involves the organization of data so as to make sense of the data and possibly predict the future using the data.
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Qualitative Data
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Data can be separated into different categories that are distinguished by some nonnumerical characteristics
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Quantative Data
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The data consist of numbers representing counts or measurments
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Measurement
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Somewhat arbitrary assignment of a number to an event or item
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Discrete Measurements
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The data can only have finite number values
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Continuous measurement
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Infinitely many possiblities for values
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Population
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The whole set or group
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Sample
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A subset of the population
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Experiment
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Set up a control group, an experimental, treat the experimental group and measure what happens.
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Simulation
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run a numerical model of the situation, probably on a computer, but not necessarily. (monopoly)
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Simple random Sample
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Everything or everybody in the population has an equal chance of being chosen
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Observational Study
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Observe and measure individuals in a way that doesn't change the response or the variable being measured
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Placebo
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No treatment or a dummy treatment
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Randomized
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Two-treatment experiment: Experiment and control group
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Lurking variables
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Unknown or hidden effects
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Bias
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Slanting of the data one way or another
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Hidden bias
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Unknown slanting of hte data one way or another
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Replication
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If the experiment is repeated, do you obtain the sam result? or are the results due to chance alone
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Generalizing results
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The results for a particular population used for the experiment may not apply to other populations.
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Histograms
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Varies from a normal bar graph by the bars always touching and hte width of hte bar represents a quantative value. Need a frequency table
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Lower class limit
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The smallest number that belongs in a different class
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Upper class limit
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The largest numbers that belong in the different classes
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Class bounddaries
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half way between two limits
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Class marks
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The midpoint of each class
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Class width
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the difference betwen 2 consecutive lower class limits or boundaries
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