Which of the answer choices best describes the appropriateness of Maria's data sample in the following vignette? Maria is conducting a study that will examine the ideas of middle school teachers, concerning the usage of iPhones in the classroom. She interviews all teachers who teach a computer software course.?
1) The sample is biased because it only includes teachers who are immersed in the technology field.
2) The sample is biased because the sample size is too small.
3) The sample is biased because the sample size is too large.
4) The sample is not biased and is appropriate for the study.