Take years on the $x$-axis and subscribers on the $y$-axis, plot the eight points, and draw a single straight freehand line passing evenly through the middle of the scatter; it slopes upward, showing a steadily increasing trend.

Data (No. of subscribers, in millions): $1976{=}12$, $1977{=}11$, $1978{=}19$, $1979{=}17$, $1980{=}19$, $1981{=}18$, $1982{=}20$, $1983{=}23$.

Method (graphical / freehand):

1. Choose the axes. Mark the years $1976$–$1983$ on the horizontal ($x$) axis and the number of subscribers (in millions) on the vertical ($y$) axis with a suitable scale (e.g. $1$ big division $= 5$ million).
2. Plot the points. Plot the eight ordered pairs $(1976,12), (1977,11), (1978,19), (1979,17), (1980,19), (1981,18), (1982,20), (1983,23)$ and join them to see the actual (irregular) series.
3. Draw the freehand trend line. Draw a single smooth straight line by hand through the middle of these points so that it lies as evenly as possible among them (roughly equal scatter above and below). It is not required to pass through any particular point. …