Here, the unit time of is year; y = yt = No. of girls per 1000 boys; t assumes 1961, 1971, …………. 2011. Taking origin at t = 1951 and scale to 10 years the given time series is written as shown in the following table:
Taking t on X-axis and y on Y-axis, the points (1, 956), (2, 948), …….., (6, 890) are plotted on the graph paper. Joining these points serially by straight lines, the curve of the given time series is obtained as follows ;
The curve passing through close to most of the points of the curve of original series is showing the trend of the given time series.
