1-Chapter 2

# 1-Chapter 2 - Lecture 1 Graphical Descriptive Techniques...

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Graphical Descriptive Techniques Graphical Descriptive Techniques Lecture 1 Lecture 1 What is Statistics? Statistics is a way to get information from data THAT’S IT!! Population VS Sample Population is the entire set of observations under study ± A descriptive measure of a population is called a parameter A sample is a subset of a population ± A descriptive measure of a sample is called a statistic The descriptive techniques we learn in this course can be used on this data

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2.0 Introduction Descriptive statistics involves the arrangement, summary, and presentation of data, to enable meaningful interpretation, and to support decision making. Descriptive statistics methods make use of ± graphical techniques ± numerical descriptive measures. The methods presented apply to both ± the entire population ± the population sample 2.1 Types of data and information A variable - a characteristic of population or sample that is of interest for us. ± Cereal choice ± Capital expenditure ± The waiting time for medical services Data - the actual values of the variables ± Interval data are numerical observations ± Nominal data are categorical observations ± Ordinal data are ordered categorical observations Types of data - examples Interval data Age -income 55 75000 42 68000 .. Weight gain +10 +5 . . Nominal Person Marital status 1 married 2s i n g l e 3s i n g l e Computer Brand 1I B M 2D e l l 3I B M
Types of data - examples Interval data Age -income 55 75000 42 68000 .. Nominal data With nominal data, all we can do is, calculate the proportion of data that falls into each category. IBM Dell Compaq Other Total 25 11 8 6 5 0 50% 22% 16% 12% Weight gain +10 +5 . . Types of data – analysis Knowing the type of data is necessary to properly select the technique to be used when analyzing data. Type of analysis allowed for each type of data ± Interval data – arithmetic calculations (1) ± Nominal data – counting the number of observation in each category (3) ± Ordinal data - computations based on an ordering process (2) Cross-Sectional/Time-Series Data Cross sectional data is collected at a certain point in time ± Marketing survey (observe preferences by gender, age) ± Test score in a statistics course ± Starting salaries of an MBA program graduates Time series data is collected over successive points in time ± Weekly closing price of gold ± Amount of crude oil imported monthly

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Computer Software Note Ensure you load Data Analysis and Data Analysis Plus Tools >> Add-Ins >> Click on Analysis toolpak (for Data Analysis) Insert CD that came with text and follow load procedure. (for Data Analysis Plus) 2.2 Graphical Techniques for Nominal data The only allowable calculation on nominal data is to count the frequency of each value of a variable. When the raw data can be naturally categorized in a meaningful manner, we can display frequencies by ± Bar charts – emphasize frequency of occurrences of the different categories. Frequencies used.
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## This note was uploaded on 10/14/2010 for the course ADMS adms 3333 taught by Professor Adms during the Spring '10 term at York University.

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1-Chapter 2 - Lecture 1 Graphical Descriptive Techniques...

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