Apoll of 1234 adults found that 65% expect an increase in environmental pollution in the next decade. assume that this poll is a simple random of all adults that was conducted by telephone. this causes some bias, because people without phones cannot be in the sample. how is this bias reflected in the confidence statement?

Donald is studying the eating habits of all students attending his school. he samples the population by dividing the students into groups by grade level and randomly selecting a proportionate number of students from each group. he then collects data from the sample. which type of sampling is used? select the correct answer below: systematic sampling convenience sampling stratified sampling cluster sampling