Random Assignment & Sampling Implications / scope of inference

Mr. Payne randomly selected 15 of his AP Computer Science students to survey them about their study habits.

• Because he randomly selected students, he can make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about the entire school.

• Because he did not randomly select students, he cannot make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about only the 5 sample students.

Mr. Payne asked for 15 volunteers from his AP Computer Science students to survey them about their study habits.

• Because he randomly selected students, he can make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about the entire school.

• Because he did not randomly select students, he cannot make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about only the 5 sample students.

Mr. Payne asked for 15 volunteers from his AP Computer Science students to survey them about their study habits.

• Because he randomly selected students, he can make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about the entire school.

• Because he did not randomly select students, he cannot make assumptions anything.

• Because he did not randomly select students, he can only make assumptions about only the 15 sample students.

Mr. Payne randomly assigned half of his AP Computer Science students to study for 3 hours, and the other half to study for 6 hours.

• Because he randomly assigned students, he can make assumptions about the entire class.

• Because he randomly assigned students, he can assume causation.

• Because he did not randomly assign students, he can assume causation.

• Because he randomly assigned students, he can only assume correlation but not causation.

Mr. Payne let his AP Computer Science students pick whether to study for 3 hours or to study for 6 hours.

• Because he randomly assigned students, he can make assumptions about the entire class.

• Because he randomly assigned students, he can assume causation.

• Because he did not randomly assign students, he can assume causation.

• Because he did not randomly assign students, he can only assume correlation but not causation.

Mr. Payne randomly selected 15 of his AP Computer Science students, and flipped a coin to decide their study habits.

• Because he randomly selected students, he can make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about the entire school.

• Because he did not randomly select students, he cannot make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about only the 15 sample students.

Mr. Payne randomly selected 15 of his AP Computer Science students, and flipped a coin to decide their study habits.

• Because he randomly assigned students, he can make assumptions about the entire class.

• Because he randomly assigned students, he can assume causation.

• Because he did not randomly assign students, he can assume causation.

• Because he randomly assigned students, he can only assume correlation but not causation.

Mr. Payne asked for 5 volunteers from his AP Computer Science students, and let them pick their study habits.

• Because he randomly assigned students, he can make assumptions about the entire class.

• Because he randomly assigned students, he can assume causation.

• Because he did not randomly assign students, he can assume causation.

• Because he did not randomly assign students, he can only assume correlation but not causation.

Mr. Payne asked for 5 volunteers from his AP Computer Science students, and let them pick their study habits.

• Because he randomly selected students, he can make assumptions about the entire class.

• Because he randomly selected students, he can make assumptions about the entire school.

• Because he did not randomly select students, he can make assumptions about only the 5 sample students.

• Because he randomly selected students, he can make assumptions about only the 5 sample students.

Researchers performed random selection and random assignment.

• Great experiment

• Bad experiment, the results only represent the sample

• Great observational study

• Bad observational study, the results only represent the sample