Consider the set of all students enrolled in your statistics course this term. Suppose you’re interested in learning about the current grade point averages (GPAs) of this group.
a. Define the population and variable of interest.
b. Is the variable qualitative or quantitative?
c. Suppose you determine the GPA of every member of e class. Would this determination represent a census or a sample?
d. Suppose you determine the GPA of 10 members of the class. Would this determination represent a census or a sample?
e. If you determine the GPA of every member of the class and then calculate the average, how much reliability does your calculation have as an “estimate” of the class average GPA?
f. If you determine the GPA of 10 members of the class and then calculate the average, will the number you get necessarily be the same as the average GPA for the whole class? On what factors would you expect the reliability of the estimate to depend?
g. What must be true in order for the sample of 10 students you select from your class to be considered a random sample?