Final answer:
Proper random sampling, like using a random number generator (option 4), ensures each individual an equal chance of being selected, making it the correct method for choosing a representative sample of students.
Step-by-step explanation:
In the context of selecting a random sample for surveying a new cell phone policy among high school students, option 4 stands out as an appropriate method. When students are selected using a random number generator, it ensures that every student has an equal chance of being included in the sample, regardless of any other characteristics such as academic performance or age. This is the essence of a random sample, in which all members of the population are equally likely to be chosen. Options 1, 2, and 3 involve volunteerism, academic performance, and age, respectively, which could introduce biases and do not guarantee that every individual has an equal chance of selection.
Proper random sampling is critical for obtaining data that is representative of the larger student body. For example, a survey that selects participants using a random number generator to choose every nth student from an alphabetical list until the desired sample size is achieved would qualify as using a systematic random sampling method, which is a form of random sampling. The selected group would thus reflect the opinions of the entire student body more accurately than a group formed by any non-random method.