help.

A librarian wants to have an employee reading contest. She asks her employees to volunteer to read as many books as possible in one week. 

Which sentences explain how randomization is not applied in this situation?

Select each ​correct answer. 

 

• The librarian is only observing her employees.
• The librarian cannot manipulate the sample or the length of the books.
• There is no control over who volunteers. 
• The librarian can select those who participate.
• There is no selection process.