Which type of study is also known as a quasi-experimental study?

Content validity refers to the extent to which a measurement instrument covers the representative aspects of the construct being measured. It is not a type of study but rather a concept used in the evaluation of tests and measures, making it unrelated to the classification of research study types.

A blind study is a research design in which participants are unaware of certain aspects of the study to reduce bias, such as whether they are receiving a treatment or a placebo. While this design can be used in experimental studies, it does not define the study as quasi-experimental, and it is not synonymous with observational studies.

Hypothesis testing is a statistical method used to determine whether there is enough evidence to reject a null hypothesis. It is a procedure used within various study designs, but it does not categorize the type of study itself, nor does it equate to quasi-experimental studies.