When to connect the dots? If each point in the series is obtained from the same source and is dependent on the previous values (. a plot of a baby's weight over the course of a year, or of muscle strength on successive contractions as a muscle fatigues), then the points should be connected by a line in a dot-to-dot fashion. If, however, the series represents independent measurements of a variable to show a trend (. mean price of computer memory over time; a standard curve of optical density vs. solute concentration), then the trend or relationship can be modeled by calculating the best-fit line or curve by regression analysis ( see A Painless Guide to Statistics ) Do not connect the dots when the measurements were made independently.