To determine the favorite music genre of students in a school, the principal surveys only the students in the school band. Why might an inference from this sample be invalid?

The sample is not random and is likely biased.

The principal should have surveyed teachers instead.

A researcher takes three separate random samples of 100 voters each to predict an election. The results show 54%, 57%, and 55% support for a candidate. What is the most reasonable conclusion?

The election is too close to call.

The samples are not representative.

The candidate's support is likely between 54% and 57%.

The candidate will lose the election.

90% of the gardening club members surveyed use brand X.

Most people in the gardening club likely use brand X.

About 90% of all people in the town use brand X.

The sample is biased if used to represent the whole town.