Intro.DOCX - Definitions of \u201cStatistics\u201d Statistics with a small \u201cs\u201d involves numbers The definition of a statistic(small s is a number that

# Intro.DOCX - Definitions of “Statistics” Statistics...

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Definitions of “Statistics”: - Statistics with a small “s” involves numbers. The definition of a statistic (small s) is a number that describes a sample of data. - Statistics (with a capital “S”) is the process of collecting, recording, describing, analyzing, and interpreting data to answer a question of interest. The Six Steps of the Statistical Process: - Based on some motivating circumstance(s), write a question of interest, which is also called a research question or research hypothesis. - Design a proper study to answer the question of interest. - Collect and record the data. - Explore the data through summary information and graphical displays. - Perform a formal statistical analysis of the data. - Based on the results of the data analysis (steps 4 and 5) answer the question of interest. It is important that this conclusion to our statistical analysis be valid to the larger group we intend to make a generalization about. But, what does "valid" mean? To understand what a valid conclusion is, we need a few more definitions. - Case: the object or individual on which data are collected. The object could be anything: person, animal, plant, etc. - Population: the group of cases to which we want to make a conclusion. The population is also called the target population or population of interest. - Sample: subset from a population on which data were or will be collected. Statistical inference is making a statement (i.e. “conclusion” or "generalization") about the population based on information collected from the sample. The idea of Statistics is that we can’t collect data on the whole population of interest. Therefore, we collect data on a subset of that population (i.e. the sample). If our sample is representative of the population, what we learn from the sample can be applied to the population of interest. As long as the study is properly designed, then we can make a valid conclusion to the population of interest based on the data from the sample. Organizing Data: - Data are often defined as information. - The first thing that must be done is to organize the data. The best way to organize data is in a spreadsheet. - Information will be collected on a number of different characteristics. These characteristics are called variables. A variable is any characteristic that is recorded on each case.
Variables are either quantitative or categorical. Categorical (qualitative, character, or text) variables: The piece of information recorded on each case falls into one of several categories or groups. Examples: hair color, ethnicity, yes/no type questions, whether or not a person talks on a cell phone while driving, military ranks. Categorical variables that have an inherent order to the categories are called ordinal variables (such as military ranks).

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