buad 310 notes for midterm 1

buad 310 notes for midterm 1 - Observations or cases form...

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Observations or cases form the rows; common attributes or variables form the columns Categorical Data Also called qualitative or nominal variables Identify group membership Numerical Data Also called quantitative or continuous variables Describe numerical properties of cases Have measurement units Size of bike (cm) and Amount spent ($) are examples Measurement Scales Nominal – name categories without implying order (categorical). E.g. gender. Ordinal – name categories that can be ordered (categorical). E.g. the good, the bad and the ugly. Interval – numerical values that can be added or subtracted (arbitrary zero).E.g. temperature. Ratio – numerical values that can be added, subtracted, multiplied or divided (makes ratio comparisons possible, zero is not arbitrary). E.g. height. Likert Scale (Ordinal – 5 to 7 Categories) Recode: building a new variable from another (recoding price into expensive or inexpensive) Aggregate: reduce rows in a data table by counting or summing values within categories Time series – data recorded over time Timeplot – graph of a time series showing values in chronological order Frequency – regular time spacing of data in a time series (e.g., daily, monthly, etc.) Cross-sectional – data observed at the same time The distribution of a categorical variable is a list of values with its associated count (frequency) A frequency table summarizes the distribution of a categorical variable A relative frequency table shows the proportion (or percentage) in each category Bar Chart Uses horizontal or vertical bars to show the distribution of a categorical variable Is called a Pareto chart when the categories are sorted by frequency (popular in quality control) Becomes cluttered with too many categories Is appropriate for ordinal categorical variables The Pie Chart Uses wedges of a circle to show the distribution of a categorical variable
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Commonly chosen to illustrate market shares or sources of revenue for a company Less useful than bar charts if we want to compare actual counts (easier to
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This note was uploaded on 04/03/2012 for the course BUAD 304 taught by Professor Cummings during the Fall '07 term at USC.

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buad 310 notes for midterm 1 - Observations or cases form...

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