Time Series and Forecasting Proctored Exam Questions With Well Elaborated Answers.

Time series - correct answer a sequence of observation on a variable measured at successive points in time or over successive periods of time Time series plot - correct answer a graphical presentation of the relationship between time and the time series variable. Time is shown on the horizontal axis and the time series values are shown on the vertical axis stationary time serie - correct answer a time series whose statistical properties are independent of time. for a stationary time series the process generating the data has a constant mean and the variability of the time series is constant over time trend pattern - correct answer a trend pattern exist if the time series plot shows gradual shifts or movement to relatively higher or lower values over a longer period of time seasonal pattern - correct answer a seasonal pattern exists if the time series plot exhibits a repeating pattern over successive periods. the successive periods are often one year intervals, which is where the name seasonal pattern comes from cyclical pattern - correct answer a cyclical pattern exists if the time series plot shows an alternating sequence of points below and above the trend line lasting more than one year. forecast error - correct answer the difference between the actual time series value and the forecast Mean absolute error (MAE) - correct answer the average of the absolute values of the forecast errors Mean sequence error (MSE) - correct answer the average of the sum of squared forecast errors Mean absolute percentage error (MAPE) - correct answer the average of the absolute values of the percentage forecast errors exponential smoothing - correct answer a forecasting method that uses a weighted average of past time series values as the forecast smoothing constant - correct answer a parameter of the exponential smoothing model that provides the weight given to the most recent time series value in the calculation of the forecast value.