QMS 703 Study Guide - Midterm Guide: Seasonal Lag, Correlogram, Forecast Error
11 Apr 2018
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Chapter 3: exploring data patterns and an introduction to forecasting techniques. Four criteria to determine whether data is useful data: reliable and accurate: source , data should be relevant: representative ,data should be consistent: definition & assumption. Data should be timely: historical pattern can be found and is still there. Data collected at single point in time: an hour,day,week, a month. Observations of data made over time cross-sectional data all observations from same time period. All observations collected at single point in time objective: extrapolate or extend the revealed relationships to the larger population time series data collected, recorded, or observed over successive increments of time. Time series data are data collected on the same observational unit at multiple time periods marihuana consumption per capita in california, by year (annual data) Horizontal: data fluctuate around a constant level or mean and are stationary. Trend data collected grow or decline over several time periods,
