The way the questionnaire is presented causes a confirmation bias, it's very loaded.
In a 1979 University of Minnesota study by Mark Snyder and Nancy Cantor, people read about a week in the life of an imaginary woman named Jane. Throughout the week, Jane did things which showcased she could be extraverted in some situations and introverted in others.
A few days passed. The subjects were asked to return.
Researchers divided the people into groups and asked them to help decide if Jane would be suited for a particular job. One group was asked if she would be a good librarian; the other group was asked if she would be a good real-estate agent.
In the librarian group, people remembered her as an introvert. In the real-estate group, they remembered her being an extravert. After this, when they were asked if she would be good at the other profession people stuck with their original assessment, saying she wasn?t suited for the other job.
The study suggests even in your memories you fall prey to confirmation bias, recalling those things which support your beliefs, forgetting those things which debunk them.