The university gym opens at 9 am on saturday mornings. one saturday morning at 8:55 am there are 27 students outside the gym waiting for it to open. should you use the same approach from part

a. to calculate the expected number of smokers among these 27 students?

No, you should not use the same approach from part (a) to calculate the expected number of smokers among these 27 students because these twenty seven students are not a random sample from the university’s total population, example it might be argued that the proportion of smokers among the 27 students outside the gym at 9 am on Saturday morning would be lower than the proper population of the university as a whole.

To add, a subset of a statistical population in wherein each member of the subset has an equal probability of being chosen is called a simple random sample.