2 A college has 400 students. A journalist wants to carry out a survey about food preferences and she obtains a sample of 30 pupils from the college by the following method.
- Obtain a list of all the students.
- Number the students, with numbers running sequentially from 0 to 399.
- Select 30 random integers in the range 000 to 999 inclusive. If a random integer is in the range 0 to 399 , then the student with that number is selected. If the number is greater than 399 , then 400 is subtracted from the number (if necessary more than once) until an answer in the range 0 to 399 is selected, and the student with that number is selected.
- Explain why this method is unsatisfactory.
- Explain how it could be improved.