AEM 201 1st Edition Lecture 2Previous LectureI. Introduction to Data and StatisticsII. Types of DataIII. Levels or Scales of Data MeasurementCurrent LectureI. Level of MeasurementII. Cross-Sectional Vs. Time Series DataIII. Methods of Data CollectionIV. Process of Statistical InferenceV. Descriptive Statistics-Organization and DisplayLevel of Measurement- Nominal and ordinal levels/scales of data summarize qualitative data- Interval and ratio levels/scales of data summarize quantitative data- The amount of information one can get from data increases as the data is classified as nominal to ratio (ratio containing the most information about the data)- The ease of collection goes down as data goes from nominal to ratio (ratio data being the hardest to collect- Data classified on a ratio level/scale is the most difficult to collect- The level/scale of measurement determines what the operations we can do on data values and give us meaning- Count Frequency (Mode) can be found in nominal, ordinal, interval and ratio data- Place Values in Rank Order (Median) can be found in ordinal, interval, and ratio data- Midrange and Arithmetic Mean can be found in interval and ratio data- Geometric Mean can only be found in ratio data- The context of any data is CRITICAL to the interpretation of resultsCross-Sectional Vs. Time Series Data- Cross-Sectional Data: values are collected from many entities during a given period of time- Time Series Data: values are collected from a single entity over several time periods- Data can be both cross-sectional and time seriesThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.Method of Data Collection- Survey/Observation: selection of a proportion of the population and measurement or observation of the values of the variables in question for the selected elements- Experimentation: manipulation of the values (or levels) of one or more (independent) variables or treatments and observations of the corresponding change in the values of one or more (dependent) variables or responseso Happens a lot in production lines- Primary Data: data collected by the user to answer a specific questiono Found by: Survey/observation Experimentation- Secondary Data: data used to answer a question other than that for which they were originally intendedo Found from: Newspapers, magazines, and books Government publications On-line data bases Websites Descriptive Statistics-Organization and Display- Summarizing qualitative datao Frequency Distribution: a tabular summary showing the absolute/relative number of elements in a data set that are in each of several mutually exclusive (non-overlapping) categories (or classes)- Types of Frequency Distributionso Absolute: summarizes the number of elements from the data set in each categoryo Relative: summarizes the proportion of elements from the data set in each categoryo Percent: summarizes the percentage of elements from the data in each