Abscissa is the horizontal axis (see xaxis) of a graph, upon which the levels of an independent variable are often represented.
Abscissa is a term used in mathematics and refers to the horizontal axis in a graph or coordinate system. In the context of psychology, it is often used to represent independent variables in research studies. Here are some examples of the use of abscissa in psychology:

Experimental design: In experimental design, the abscissa is often used to represent the independent variable, which is the variable that the researcher is manipulating. For example, in a study examining the effects of caffeine on memory, the abscissa may represent the different levels of caffeine administered (e.g., 0mg, 50mg, 100mg).

Data visualization: In data visualization, the abscissa is used to plot data points along the horizontal axis. For example, a scatterplot may have the abscissa represent one variable (e.g., age) and the ordinate represent another variable (e.g., reaction time).

Statistical analysis: In statistical analysis, the abscissa is used to represent the predictor variable in regression analyses. For example, in a study examining the relationship between stress and performance, the abscissa may represent the level of stress experienced, and the ordinate may represent the level of performance.
Overall, the abscissa is a useful tool in psychology research for representing and analyzing independent variables, as well as visualizing and interpreting data.