Why does this graph have both solid and dotted lines? What does that mean?
The presence of both solid and dotted lines in a graph usually indicates different types of data or distinguishing factors. Here are a few possible reasons for their usage:
1. Differentiated data: Solid lines often represent actual data points or values, while dotted lines may represent predicted or estimated values. This helps to distinguish between observed and projected data.
2. Different variables: Solid lines might represent one variable or dataset, while dotted lines represent another. This could occur when comparing two or more sets of data that are related but distinct.
3. Confidence intervals: Dotted lines could indicate the upper and lower bounds or confidence intervals of a data set. These lines help illustrate the range within which the true values are likely to fall.
4. Trend lines: Solid lines often represent trend lines or regression lines that depict the general direction or pattern of the data. Dotted lines may indicate extrapolations beyond the observed data points.
5. Assumptions or significance: Dotted lines may delineate thresholds, boundaries, or levels of significance in a graph. They can help identify critical values or reference points for understanding the data.
In summary, the specific meaning of solid and dotted lines in a graph depends on the context and purpose of the graph. Proper labeling or a legend accompanying the graph should explain the significance of each line type.