The document describes different types of experimental research designs: pre-experimental, quasi-experimental, and true experimental. Pre-experimental designs lack random assignment and include one-shot case studies, one-group pretest-posttest, and static group comparisons. Quasi-experimental designs resemble true experiments but lack random assignment, using time series or non-equivalent control groups. True experiments randomly assign participants to experimental and control groups, including post-test-only, pre-post-test, and Solomon four-group designs to precisely test hypotheses.