Applied Statistics Example . Fit a trend line by the method of freehand method for the given data. Year Sales O X ′ Y ′ Y Trend Line Original Data Sales Fig: . The trend drawn by the freehand method can be extended to predict the future values of the given data.
However, this method is subjective in nature, predictions obtained by this method depends on the personal bias and judgement of the investigator handling the data. Note (ii) Method of Semi-Averages In this method, the semi-averages are calculated to find out the trend values. Now, we will see the working procedure of this method. Procedure: (i) The data is divided into two equal parts.
In case of odd number of data, two equal parts can be made simply by omitting the middle year. (ii) The average of each part is calculated, thus we get two points. (iii) Each point is plotted at the mid-point (year) of each half. (iv) Join the two points by a straight line.
(v) The straight line can be extended on either side. (vi) This line is the trend line by the methods of semi-averages. Example . Fit a trend line by the method of semi- averages for the given data.
Year Production Since the number of years is odd(seven), we will leave the middle year’s production value and obtain the averages of first three years and last three years. Year Production Average (left out) Table . O X ′ Y ′ Y Fig: . Example .
Fit a trend line by the method of semi- averages for