Same sign add different sign subtract that means if their both positive you add and if one is positive and the other is negative you subtract
Answer:
The provided study is an experiment.
Step-by-step explanation:
Consider the provided information.
Observational study: In this study observer only observe the subjects, and measure variables of interest without allocating treatments to subjects.
For example: you want to examine the side effect of smoke on lung.
Experiment study:The researchers are applying treatments to experimental units in the research, then the effect of the treatments on the experimental units is observed.
For example: Flipping a coin
Now consider the provided information:
Thirty university students are divided into two groups. One group receives free tutoring in mathematics comma the other doesn't. After one semester comma scores on final mathematical examinations are compared.
Here, the researcher applying treatment to experimental units.
Thus, the provided study is an experiment.
