In each of the following situations, the sampling frame does
not match the population, resulting in undercoverage. Give examples of population
members that might have been omitted.
The population consists of all 250 students in your large statistics class. You
plan to obtain a simple random sample of 30 students by using the sampling
frame of students present next Monday.

Here is how I see it. There might not be all 250 students in class on that Monday. Is that what they mean by under coverage?

Question

In each of the following situations, the sampling frame does
not match the population, resulting in undercoverage. Give examples of population
members that might have been omitted.
The population consists of all 250 students in your large statistics class. You
plan to obtain a simple random sample of 30 students by using the sampling
frame of students present next Monday.

Here is how I see it. There might not be all 250 students in class on that Monday. Is that what they mean by under coverage?