She only asked the students in her ballet class, which is probably biased toward ballet. She should survey everyone in The Dance Academy. That way, the answers won't be biased.
Given that a dance student wants to know the favorite type of dance class for students at The Dance Academy. She surveys each student in her ballet class.
When she surveys only students in ballet class, she is taking a biased sample who already decided to pursue ballot dance.
Hence the survey is not correct and will not give accurate results.
She must select equal number of random students from each dance group and conduct the survey to get a more reliable result.
