Reference no: EM132852306

1. If a study uses random assignment, what does this mean?

A. The treatments used in the study are randomly selected.

B. Subjects in the study are randomly chosen from the population.

C. Subjects in the study are allocated at random among all the treatments.

D. The researcher who conducts the study is selected by a random process.

E. The manner in which the results of the study are analyzed is randomly determined.

2) If you name a cow and regularly mention the cow's name when you are talking to it, will the cow yield more milk than a cow who is not talked to by name? To investigate this, researchers surveyed 516 dairy farmers in the United Kingdom. They asked each farmer if they regularly referred to their cows by name. They also asked each farmer how much milk their cows produced each year. The researchers found that cows who were regularly referred to by name produced an average of 500 more points per year of milk than cows who were not regularly referred to by name. Based on this information, which of the following statements is correct?

A. The explanatory variable is the type of food fed to the cows.

B. The individuals are the researchers.

C. This study is an example of an experiment.

D. The response variable is the amount of milk produced by the cows.

E. None of the above answer options are correct statements

3) Suppose the results of a study are deemed to be "statistically significant." What does this mean?

A. The results of the study would rarely occur just by chance alone.

B. We should conclude that the explanatory variable causes changes in the response variable.

C. The study must have included a control group.

D. The study was double-blind.

E. There were no lurking variables in the study.

5) A study was recently published about the effect of cannabis use on symptoms of post-traumatic stress disorder (PTSD). In the study, data was collected from 404 medical cannabis users who self-identified as suffering from PTSD. All of these individuals used a special app in order to track their cannabis use and the changes in their PTSD symptoms over time. The researchers observed that for all of the cannabis users in the study, symptoms of PTSD were reduced by more than 50% immediately after cannabis use, and higher doses of cannabis were associated with larger reductions in symptoms. A critic of the study mentioned that there was no control group. Why would it be important to have a control group in this kind of study?

A. A control group would allow the results of the study to be generalized to a larger population.

B. A control group automatically creates what is known as a double-blind experiment.

C. A control group would allow the researchers to better access whether the reduction in PTSD symptoms might be due to the placebo effect.

D. A control group would completely eliminate all possible lurking variables.

E. A control group would ensure statistically significant results.

6) Is the height of a one-layer cake (in inches) affected by baking temperature and the rate at which the batter is stirred? A local bakery designs an experiment in order to investigate the effects of temperature (300 degrees F, 350 degrees F, or 375 degrees F) and stirring rate (60 rpm, 90 rpm, or 120 rpm) on cake height. If several cakes are baked at each of the different combinations of temperature and stirring rate, how many treatments does this experiment have?

A. One

B. Two

C. Three

D. Six

E. Nine

7) An experiment is conducted in order to examine the effect of mood on reaction time. Participants in the experiment are randomly assigned to watch either a funny movie or a sad movie before they finished a reaction time task. You later learn that the participants who watched the funny movie completed the reaction time task early in the day whereas those who watched the sad movie completed the reaction time task late in the evening. We would consider this to be an example of

A. an observational study.

B. a double-blind experiment.

C. confounding.

D. statistical significance.

E. the placebo effect.

8) Can chewing gum while attempting to learn new material improve attention and memory for that material? Researchers randomly assigned college students to either chew gum while studying a physiology lesson about the function of the heart or to not chew gum while studying the lesson. At the end of the lesson, the students completed a multiple-choice test about the contents of the lesson. Those students who chewed gum during the lesson correctly answered more multiple-choice questions than those students who did not chew gum during the lesson. What is the explanatory variable in this study?

A. Age of the students

B. Length of the lesson

C. Whether or not gum was chewed while studying

D. Score on the multiple-choice test

E. Flavor of the gum that was chewed

9) An experiment was designed in order to investigate whether antidepressants can help people quit smoking. The subjects in the experiment were 450 adults over the age of 18 years who were all highly motivated to quit smoking. Half of these subjects were randomly assigned to take 300 mg daily-for 45 weeks-of an antidepressant known as bupropion. The other half were randomly assigned to take a sugar pill daily for 45 weeks. The sugar pill looked like bupropion but did not contain any of the active ingredients found in bupropion. At the end of the 45-week period, it was observed that 57.6% of the adults in the bupropion group were no longer smoking, compared to 44.3% of the adults in the sugar pill group. If we learn later that not all subjects followed the directions about the need to take their pill at the same general time each day, we'd consider "whether or not directions were followed" to be a(n)

A. double-blind study.

B. lurking variable.

C. placebo effect.

D. explanatory variable.

E) response variable