3. A college manager wants to survey students' opinions of enrichment activities. She decides to survey the students on the courses summarised in the table below.
| Course | Number of students enrolled |
| Leisure and Sport | 420 |
| Information Technology | 337 |
| Health and Social Care | 200 |
| Media Studies | 43 |
Each student takes only one course.
The manager has access to the college's information system that holds full details of each of the enrolled students including name, address, telephone number and their course of study. She wants to compare the opinions of students on each course and has a generous budget to pay for the cost of the survey.
- Give one advantage and one disadvantage of carrying out this survey using
- quota sampling,
- stratified sampling.
The manager decides to take a stratified sample of 100 students.
- Calculate the number of students to be sampled from each course.
- Describe how to choose students for the stratified sample.