Plot (year, boxes) and draw one smooth freehand line balancing the points above and below it; the fitted line rises from about 1–2 (ten-thousands) near 1977 to about 7–8 near 1984, i.e. an increasing trend.

Data (boxes sold, in ten-thousands):

Graphical (freehand) method — procedure:

1. Take years on the X-axis and the number of boxes (ten-thousands) on the Y-axis, choosing a suitable scale (e.g. 1 unit = 1 year on X, 1 unit = 1 ten-thousand on Y).
2. Plot the eight points $(1977,1)$, $(1978,0)$, $(1979,3)$, $(1980,8)$, $(1981,10)$, $(1982,4)$, $(1983,5)$, $(1984,8)$ and join them to see the actual (fluctuating) series.
3. Draw a single smooth freehand straight/curved line through the scatter so that it moves evenly among the points — roughly as many points lie above the line as below it, and the line ignores the short-term ups and downs. …