In a proportional relationship when x = 9 and y = 15 what is the value of y when x = 48?

Please see answer in explanatory column

Step-by-step explanation:

STEP 1 - Since the survey is not an experimental one which occurs in a laboratory with a control and interference with sample.

Then the professor will use an observational study is in which he will observe the  behavior of the students  in a systematic manner without interfering with the students behavior so as to know how satisfied the students are with the course.   After getting to know how satisfied the students are for his course he would record the behavior that he or she observes and rate accordingly

STEP 2:The sampling strategy the Professor can use in carrying out the research is a Stratified sampling which occurs when the population to be observed is divided into groups known as strata which contains similar cases grouped together, then a second sampling, mostly a random sampling where the professor will randomly sample few students from the different strata to get his observations. for example, the students divided in 4 groups of 40 students represents each strata placed in common according to the different teaching assistant, then the professor can then randomly sample few students from each strata from a class of the 120 students.