Data Analysis and Decision Making Question And Answers.

Data Analysis and Decision Making Question
And Answers

Population - Correct Answer - (statistics) the entire aggregation of items from which samples can be
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drawn
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Sample - Correct Answer - A relatively small proportion of people who are chosen in a survey so as to be
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representative of the whole.
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variable - Correct Answer - Attribute or measurement of members of a population
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Observation - Correct Answer - list of all variable values for a single member of a population
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DATA SET - Correct Answer - array of data, variables in columns, observations in rows variable names in
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tops of rows
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data type - Correct Answer - numerical v. categorical, discrete v. continuous, cross-sectional v. time
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series, categorical=nominal or ordinal
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dummy variable - Correct Answer - is a variable for wich all cases falling into a specific category assume
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the value of 1, and all cases not falling into that category assume a value of 0
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binned variable - Correct Answer - numerical, categorized into bins/ranges
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counts of categories - Correct Answer - numbers of observations in various categories
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Percentiles - Correct Answer - values that have specified percents BELOW them
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quartiles - Correct Answer - 25%, 50% or 75% below them
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concatenate - Correct Answer - string together 2 or more peices of text (&)
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IQR Interquartile Range - Correct Answer - 3rd -1st quartile 75-25
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Variance - Correct Answer - average of quared deviations from the mean
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standard deviation - Correct Answer - measure of variability in same units as observations
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Square root of viarance
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empirical rules - Correct Answer - μ +/- 1σ encloses about 68.26% of X's
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μ +/- 2σ covers about 95% of X's
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