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Unformatted text preview: lecture 4, Descriptive Statistics for Categorical Data Frequency and Relative Frequency Tables Bar Charts and Pie Charts Mode and Median lecture 4, Descriptive Statistics for Categorical Data Outline 1 Frequency and Relative Frequency Tables 2 Bar Charts and Pie Charts 3 Mode and Median lecture 4, Descriptive Statistics for Categorical Data Frequency and Relative Frequency Tables Bar Charts and Pie Charts Mode and Median lecture 4, Descriptive Statistics for Categorical Data Example 1. Amazon Hosts • 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). • Question of interest: Which hosts send the most visitors to Amazon’s website? (So that Amazon can further decide whether it’s worthwhile to pay more to keep links on certain busy sites.) lecture 4, Descriptive Statistics for Categorical Data Frequency and Relative Frequency Tables Bar Charts and Pie Charts Mode and Median lecture 4, Descriptive Statistics for Categorical Data Data Date Purchase Amount ($) Host Region . . . . . . . . . . . . . . . 21Sep2002 No yahoo.com Northeast 21Sep2002 Yes 65.97 msn.com West 21Sep2002 Yes 10.00 google.com South 22Sep2002 No Midwest 22Sep2002 Yes 25.10 yahoo.com Northeast 22Sep2002 Yes 125.08 Midwest . . . . . . . . . . . . . . . 1 • Data set consists of 188,996 visits • To answer the question of interest we must describe the distribution of Host • Host is a categorical variable 1 The Host field is left blank when the customer typed amazon.com into a browser. lecture 4, Descriptive Statistics for Categorical Data Frequency and Relative Frequency Tables Bar Charts and Pie Charts Mode and Median lecture 4, Descriptive Statistics for Categorical Data Frequency and Relative Frequency Tables Frequency and Relative Frequency Tables For categorical data, names identify the different categories • This data can be summarized using a frequency table : • A table that summarizes the number of items (frequency) in each of several nonoverlapping classes or a relative frequency table : • A table that summarizes the proportion of items in each class • For each class, proportion =relative freqency= the frequency of the class divided by the total number of observations lecture 4, Descriptive Statistics for...
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This note was uploaded on 12/04/2010 for the course ISOM ISOM111 taught by Professor Anthonychan during the Fall '09 term at HKUST.
 Fall '09
 AnthonyChan

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