Answer:
A scientific experiment is performed to test the hypothesis which is the predicted idea about the natural phenomenon based on the previous research.
The experimental design must contain three types of variables: the variable which can be manipulated (independent variable). the variable which is to be tested (dependent variable) and the variable which is kept constant throughout the experiment (constant variable).
The experimental sample is divided into two groups: the experimental group which includes the factor to be studied and the control group which lack the factor to be studied.
In the given question,
1. Hypothesis: liquid spurt when falls form a height.
2. Independent Variable: Height of hole which gets changed
3. Dependent Variable: Range of squirt which is to be tested
4. Constant (at least one):the volume of filled liquid is kept constant
5. Control: 4 identical cartons which are punched with a hole of the same size.
6. A number of groups: two (control and experimental)
7. Number of trials per group: four