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Unformatted text preview: Data Tables Types of Data Describing Categorical Data Outline Data Tables Types of Data Categorical and Numerical Data Time Series Data and Cross Sectional Data Describing Categorical Data Frequency and Relative Frequency Tables Bar Charts and Pie Charts Mode and Median 1/24 ISOM 2500 Lect 2: Types of Data, Describing Categorical Data Data Tables Types of Data Describing Categorical Data DISCOVERY WITH STATISTICAL TOOLS • Just looking at lists of raw numbers reveals little, especially for large data sets. • Finding a revealing view of the data is the key to effective statistical analysis. • Different types of displays: graphical and numerical. • Goal is to focus attention on essential features of data; to separate reproducible patterns from random, coincidental features. • Relevance in decision making • Summarization can be very useful when using data to form decisions. • Avoid distraction from extraneous features of data. 2/24 ISOM 2500 Lect 2: Types of Data, Describing Categorical Data Data Tables Types of Data Describing Categorical Data Data Tables • Data: a collection of numbers, labels, or symbols, and the context of those values. • Data tables : a data table is a rectangular arrangement of data with rows and columns • Observations or cases form the rows; common attributes or variables form the columns • Data tables • Organize data to yield meaningful information • Provide context (e.g., who, what, when) • Improve interpretability with meaningful names, formatting and units 3/24 ISOM 2500 Lect 2: Types of Data, Describing Categorical Data Data Tables Types of Data Describing Categorical Data Data Tables, Example 1 Every day, more than 100 million shoppers visit Amazon.com, either by typing the address into their browser or by clicking through from another web site (host). The following table describes some visits. Visitor ID Purchase Amount ($) Host Region A No yahoo.com Northeast B No msn.com West C Yes 10.00 google.com South D No recipesource.com Midwest E Yes 25.10 N/A Northeast F Yes 125.08 google.com Midwest . . . . . . . . . . . . . . . 4/24 ISOM 2500 Lect 2: Types of Data, Describing Categorical Data Data Tables Types of Data Describing Categorical Data Categorical and Numerical Data Time Series Data and Cross Categorical and Numerical Data Most variables consists of either categorical or numerical data • Categorical Variables • Also called qualitative or nominal variables • Identify group membership • Example: “Purchase”, “Host”, “Region” in Example 1 • Numerical Variables • Also called quantitative or continuous variables • Describe numerical properties of cases • Have measurement units • Example: “Amount” in Example 1 5/24 ISOM 2500 Lect 2: Types of Data, Describing Categorical Data Data Tables Types of Data Describing Categorical Data...
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This note was uploaded on 12/20/2011 for the course ACCT/MGMT 2010 taught by Professor A during the Spring '11 term at HKUST.
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