http://dictionary.cambridge.org/dictionary/american-english/questionnaire?q=questionnairequestionnaire
Definition
› a written list of questions that people are asked so that information can be collected
I understand this phrase, but I would like to know - is this sentence absolutely correct? Shouldn't there be a preposition or something else?
E.g.:
a written list of questions by which people are asked so that...
or
a written list of questions that people are asked with (by) so that...
Thank you.