Semi average method

Free Hand Curve Method Semi average method

1. Free Hand curve Method

2. METHOD OF SEMI-AVERAGE

3. METHOD OF SEMI-AVERAGE This method is as simple and relatively objective as the free hand method. The data is divided in two equal halves and the arithmetic mean of the two sets of values.

4. Advantages This method is simple to understand as compare to other methods for measuring the secular trends. Everyone who applies this method will get the same result.

5. Disadvantages The method assumes a straight line relationship between the plotted points without considering the fact whether that relationship exists or not. If we add more data to the original data then we have to do the complete process again for the new data to get the trend values and the trend line also changes.

6. Explanation of the Method When data is even:  In this case, the time series will be into two parts and then we calculate the average of each part. Suppose if we have 10 years data then we divide it into 5 -5 years and then we will calculate the first five-year average and the next five-year When data is odd:  In this case, we just leave the middle data and we will follow the above-said procedure for the rest.

7. Fit a trend line by the method of semi-averages for the given data.