Final answer:
The study is an observational study because there is no treatment applied to the subjects, and the major issue with the study is that the sample size is too small, which could lead to unrepresentative results and potential Type II errors.
Step-by-step explanation:
The study described in the question is an observational study because the researcher does not attempt to modify or apply a treatment to the individuals involved. Instead, natural occurrences of systolic blood pressure levels among the selected male and female students are simply recorded for analysis.
A major problem with the study is that the sample size is too small. A sample of only eight students (four male and four female) is unlikely to be representative of the general population, and therefore, the results could be affected by random variation and may not be generalizable. This size limitation also heightens the chance of Type II errors, where real effects or differences are not detected because the sample does not provide enough data for conclusive analysis.