Saturday, June 15, 2019

Statistical computation of maximum likelihood estimates using R Math Problem

Statistical computation of maximum likelihood estimates victimization R - Math line ExampleSMA do not account for seasonal changes. The duration of the sorrowful average can best be determined according to the type of coating data to forecast. Long era periods gives smoother response by re touching random variations but react slower to changes in the data as it lags the trend. Short time periods produce more oscillation but closely follow the trend. SMA is calculated by averaging the most recent number of unquestionable values. SMA is calculated by using the following equation (Chase & Jacobs 2006) Where Ft Forecast for coming periodAt-1Actual value in the pastAt-2, At-3,Actual values two, three, periods ago.NNumber of periods to be averagedIn the attached excel document, SMA is calculated for three periods three, four, and five. Different n time periods will produce different results of data values. The values of MAD similar to each period are shown in the following tableTable 1 MAD values for different periods of SMATime Period (n)MAD 34.3643.1053.95Table one demonstrates that the smallest value of MAD exists for the period of n=4. This indicates that the type of data being analyzed is best estimated using a period of four. simulacrum 1 SMA for periods of 3,4, and 5. Figure one confirms the results of MAD analysis from table one. The best fit trend line is the SMA for n=4. This line follows the actual data curve specially on the 15th, 22, and 25 where major change occurred in land up speed. The period that best fits the actual data is dependent on the type of data analyzed which is the wind speed. Weighted Simple Moving Average (WSMA)A weighted moving average puts different weights to each element, providing that the fondness of all weights equals 1. Weights are...Short time periods produce more oscillation but closely follow the trend.In the attached excel document, SMA is calculated for three periods three, four, and five. Different n time periods will produce different results of data values. The values of MAD corresponding to each period are shown in the following tableFigure one confirms the results of MAD analysis from table one. The best fit trend line is the SMA for n=4. This line follows the actual data curve specially on the 15th, 22, and 25 where major change occurred in wind speed. The period that best fits the actual data is dependent on the type of data analyzed which is the wind speed.A weighted moving average puts different weights to each element, providing that the sum of all weights equals 1. Weights are chosen by experience and trial and error. A normal rule applies that recent past is more indicative of the future and should get higher weighting. However, if the data are seasonal weights should be established accordingly. The weighted moving average advantage over the simple moving average is the ability to vary the effects of past data.In the excel document, in the Weighted SMA sheet, the weights of the m oving average are determined by trial and error to produce the least value of MAD since there is no expert opinion as to guide the setup of

No comments:

Post a Comment

Note: Only a member of this blog may post a comment.