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This introductory text explores the basic principles of statistics, from collecting and organizing data to interpreting and presenting numerical information. Learn about experimental units, variables, observations, populations, samples, and different levels of measurement. Discover the difference between descriptive and inferential statistics, as well as the types of variables and scales used in statistical analysis.
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Chapter 1 - Introduction Math 22 Introductory Statistics
What is Statistics? • Statistics - Involves the collection, organization, interpretation, and presentation of numerical information.
Introductory Terms • Experimental Units - Subjects • Variable – A characteristic of interest about each individual element of a population or sample • Observations – Particular information that we collect from each subject. • Data Set – Collection of observations.
Items That We Might Want to Study • Population - Collection of all objects or items that are of interest in a statistical study. • Sample - A finite portion (subset) of the population that is used to study the characteristics of concern in the population. • Target Population - Population of interest in the study.
Items That We Might Want to Study • Parameter – A numerical value summarizing the entire population • Sample Statistic – A numerical value summarizing the sample data. • Census - A sample consisting of the entire population. (An attempt to sample the entire population)
Descriptive and Inferential Statistics • Descriptive Statistics - Describes the state of the data which has been collected. • Inferential Statistics - Generalizations or conclusions that extend beyond the collected data, what we call the population.
Levels of Measurement • Nominal Scale Variables that categorize without any form of natural ordering. • Ordinal Scale Variables that categorize with a form of natural ordering • Interval Scale Require a physical unit of measure. There is no absolute zero (starting point).
Levels of Measurement • Ratio Scale Very similar to interval scale variables. The key difference is that ratio scale variables have an absolute starting point, an absolute zero.
Types of Measurements • Numerical Variable (quantitative variable) - A variable whose values are numbers obtained by a measurement. • Discrete Variable • Continuous Variable
Types of Measurements • Categorical Variable (Qualitative Variable) - Variable whose values are classifications or categories. (i.e. Coding)