Week 2 Quiz

A student says, "People who sleep more do better on next-day quizzes." Before any data are collected, she writes: "Students who report 8 or more hours of sleep will score higher on tomorrow's quiz than students who report fewer than 6." What is the second statement?

Select one.

• A theory, because it is a broad explanation already backed by evidence
• A hypothesis, because it is a specific prediction that data could prove wrong
• A correlation coefficient, because it states how strongly two measures move together
• A case study, because it describes one group of students in depth

Ebbinghaus (1885) studied forgetting by memorizing lists of nonsense syllables and relearning them later. What was his operational definition of memory?

Select one.

• How confident he felt that he still knew each list
• How many lists he could memorize in a single day
• Percent savings: how much less time relearning took than first learning
• How vividly he could picture a list after a month

In an illustrative dataset, 10 students reported their hours of sleep and their next-day quiz score out of 20. Nobody's sleep was changed, and r = 0.8457. Which conclusion does this design support?

Select one.

• Getting more sleep causes students' quiz scores to rise
• Sleep is the independent variable and the quiz score is the dependent variable
• About 84.57% of the students scored higher because they slept more
• In this sample, students who slept more tended to score higher

For the 10 students' hours of sleep and next-day quiz scores, r = 0.8457. How would you describe this correlation?

Select one.

• Positive and strong: the two measures tend to rise together
• Positive and weak: the two measures barely move together
• Negative and strong: one measure tends to fall as the other rises
• Near zero: there is little linear association between them

In Loftus and Palmer (1974), students watched films of car accidents and were asked how fast the cars were going when they "smashed," "collided," "bumped," "hit," or "contacted" each other. "Smashed" averaged 40.8 mph and "contacted" averaged 31.8 mph. Which labels are correct?

Select one.

• The IV is the speed estimate, and the DV is the verb in the question
• The IV is the verb in the question, and the DV is the speed estimate
• The IV is the film of the accident, and the DV is the verb in the question
• There is no IV or DV, because both are measured variables

A week after the films, 32% of students who heard "smashed" reported broken glass that was never there, against 14% for "hit" and 12% for a control group asked no speed question. What feature of the design lets Loftus and Palmer (1974) say the wording caused this difference?

Select one.

• The large number of students in each group
• The use of films instead of real accidents
• Random assignment of students to the verb conditions
• Random sampling of the students from a population

The illustrative sleep and quiz-score data show r = 0.8457. Which of these could explain the association without sleep itself raising scores? Select all that apply.

Select every option that applies.

• Students who finished studying earlier could both sleep more and score higher
• A lighter work schedule could give a student both more sleep and more study time
• A good day of studying could make it easier to fall asleep that night
• Because 0.8457 is close to +1, the link must be a cause
• Because each student chose their own bedtime, the groups were randomly assigned

A company with 2,000 employees draws 100 names from its full staff list, then flips a coin to decide which of those 100 get a new afternoon break. What does the name draw accomplish?

Select one.

• It lets the company claim the new break caused any difference
• It makes the measure of the break more reliable
• It replaces the need for a control group
• It lets the company generalize its results to the whole staff

A bathroom scale that always reads exactly five pounds lighter than a person's true weight is reliable but not valid.

True or false.

• True
• False

Milgram (1963) reported that 65% of participants (26 of 40) continued to the 450-volt switch. Participants believed the shocks were real, though none were given. Under today's research ethics rules, what must follow a deception like this?

Select one.

• Debriefing that reveals the true purpose and the deception
• A second session that repeats the same deception
• A survey asking whether participants enjoyed the study
• Publication of each participant's name and responses