What does it mean when you have a solid dot on your graph?

Answer 1

When you have a solid dot on a graph, it typically represents a data point that is included in the data set and is significant for the analysis being conducted. The solid dot indicates that the specific value represented by the dot is part of the plotted data and is not an outlier or a missing value. In some cases, a solid dot may also signify a specific condition or event that occurred at that data point in the context of the graph.

Answer 2

It usually means that the end point is included in the range of values that you are intereted in.

For example, a graph of 0 ≤ x < 1 would have a solid dot at 0 and a hollow circle at 1

while a graph of 0 < x ≤ 1 would have a hollow circle at 0 and a solid dot at 1.