UASTAT141Ch1-6 - Chapter 1 Defn Statistics 1 are commonly...

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Chapter 1 Def’n: Statistics: 1) are commonly known as numerical facts 2) is a field of discipline or study Here, statistics is about variation. 3 main aspects of statistics: 1) Design (“Think”): Planning how to obtain data to answer questions. 2) Description (“Show”): Summarizing the obtained data. 3) Inference (“Tell”): Making decisions and predictions based on data. Chapter 2 - Data Def’n: A population consists of all elements whose characteristics are being studied. e.g. UofA students A sample is a portion of the population selected for study. e.g. UofA students in this section A parameter is a summary measure calculated for population data. A statistic is a summary measure calculated for sample data. Types of statistics: Descriptive: methods to view a given dataset. e.g. averages, histograms Inferential: methods using sample results to infer conclusions about a larger population. e.g. t-tests, simple linear regression Def’n: A variable is any characteristic that is recorded for subjects in a study. - Qualitative (categorical): cannot assume a numerical value but classifiable into 2 or more non-numeric categories. e.g. gender, smell, grades - Quantitative (numerical): measured numerically. - Discrete: only certain values with no intermediate values. e.g. integers, grades - Continuous: any numerical value over a certain interval or intervals. e.g. GPA, gas prices Chapter 3 – Categorical Data Graphs Def’n: A frequency table (for qualitative data) is a listing of possible values for a variable, together with the # of observations for each value. Major Frequency ( f ) Relative frequency Percentage (%) Science Arts Business Nursing Other Relative frequency = f f Percentage = Relative frequency × 100%
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Graphical Summaries Def’n: A bar chart is a graph of bars whose heights represent the (relative) frequencies of respective categories. e.g. (preceding table used in class) Look for : frequently and infrequently occurring categories. A pie chart is a circle divided into portions that represent (relative) frequency belonging to different categories. e.g. (preceding table used in class) Look for : categories that form large and small proportions of the data set. A segmented bar chart uses a rectangular bar divided into segments that represent frequency or relative freq. of different categories. e.g. (preceding table used in class) Chapter 4 – Numerical Variable Graphs Def’n: A stem-and-leaf display has each value divided into two portions: a stem and a leaf. The leaves for each stem are shown separately. (Values should be ranked.) Look for : - typical values and corresponding spread
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UASTAT141Ch1-6 - Chapter 1 Defn Statistics 1 are commonly...

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