Final answer:
Data can be either quantitative or qualitative, and can be displayed using various types of charts. Observational studies are categorized into three types. The four chart types mentioned in the question include quantitative, qualitative, exploratory, and observational.
Step-by-step explanation:
In general, data is either quantitative (a measure of how much of something) or qualitative (a description of something). There are many ways to display data, and the type of data you collect will determine the type of data plot you will need. Simple data plots include pie charts, bar charts, timelines, histograms, and scatter plots.
When it comes to observational studies, there are three types: cross-sectional, case-control, and cohort studies. Each type has its own advantages and disadvantages.
Therefore, the four chart types mentioned in the question include quantitative, qualitative, exploratory, and observational.