Q1) Label each study as either an observational study, an experiment, or neither.

Group of answer choices

• From December 2007 through March 2012, researchers at the University of Pittsburgh studied a new medication to treat osteoporosis in frail elderly women. The researchers administered a daily dose of the medication or a placebo by injection along with calcium and vitamin D supplements. Then the researchers measured the hip and spine bone density of each patient at 12 and 24 months. Results were published in the Journal of the American Medical Association (JAMA) in April 2015.

[ Choose ]

Neither

Experiment

Observational study

• The math department recently purchased new learning software for their freshman math classes. The instructors want to use the learning software instead of a textbook. So they decide to study the effectiveness of the software. First they test the skills and concept mastery for a number of the freshman math students. Then they randomly divide the students into two groups. One group uses the learning software for a particular lesson and the other group uses the regular textbook. Then the instructors retest all of the students and compare the improvement in the skills and concept mastery for the two groups.

[ Choose ]

Neither

Experiment

Observational study

• One way MSNBC solicits the opinions of its news consumers is through the organization's online Speak Out surveys. Using social media and its television and radio news shows, MSNBC encourages its news consumers to go online and respond to various opinion polls about trending topics. Typically the polls remain open. In one ongoing Speak Out poll, MSNBC asks whether marijuana should be legalized, decriminalized, or illegal. As of May 10th, 2015, more than 26,000 people had responded to the poll, and 77% indicated that marijuana should be legalized.

[ Choose ]

Neither

Experiment

Observational study

Q2) Whooping cough vaccine: Some parents fear that vaccinations may have adverse long-term effects on their children's health. In 2009, the Journal of the American Academy of Pediatrics published research on a routine childhood vaccine for whooping cough. The researchers studied 6,811 children born between 1993 and 1997 in Leicestershire, UK. Parents answered questions over a period of more than 10 years about their children's respiratory symptoms. Researchers then linked this data to independently collected vaccination data from the National Health Service database. They divided the children into groups based on vaccine history (complete vaccines, partial vaccines, no vaccines) and compared respiratory symptoms. The study provided no evidence that vaccinated children were more likely to have respiratory problems such as wheeze and asthma.

Students in a statistics class were asked to summarize the results of this study. Which of the student statements is an appropriate summary? Check all that apply.

Group of answer choices

-Vaccinating infants against whooping cough is not associated with a greater incidence of wheeze and asthma in later life.

-Vaccinating against whooping cough does not increase the risk of wheeze and asthma in later life.

-Whooping cough vaccinations are not linked with respiratory problems, such as wheeze and asthma, in later life.

-Whooping cough vaccinations do not cause respiratory problems, such as wheeze and asthma, in later life.

Q3) The math department faculty at a large university wanted to know what portion of the student body believes students should be able to enroll in any math class without meeting a prerequisite. The statistics department offered to cooperate in conducting a survey, and a simple random sample of 500 students was selected from all the students enrolled in statistics classes. A survey form was sent by email to these 500 students and 236 responded.

To identify the population and the sample for this study, label each item on the left with a term on the right. Note - any given term on the right may be used more than once or not at all.

Group of answer choices

• All students at the university(neither,population ,sample)

• All students enrolled in a statistics class(neither,population ,sample)

• 500 students who received the email survey(neither,population ,sample)

• 236 students who responded to the email survey (neither,population ,sample)

Q4) Advice columnist Ann Landers once asked her divorced readers whether they regretted their decision to divorce. She received approximately 30,000 replies. Of the 30,000, about 23,000 came from women. Nearly 75% said they were glad they divorced. Of these, most said they wished they had divorced sooner.

Which is the most accurate statement about the survey?

Group of answer choices

This sample is large (approximately 30,000) so the results are representative of the population of divorced people in the U.S.

The results are believable, so the survey is not biased.

This is a convenience sample and is biased by an unequal number of males and females.

This survey is biased by voluntary participation and probably overestimates that percentage who are glad they divorced.

Q5) Which question is best answered by an experiment?

Group of answer choices

Is there an association between the number of hours college students spend each week on Facebook and their college GPA?

Do the majority of community college students plan to vote in the next presidential election?

Does use of computer-aided instruction in college math classes improve test scores?

Are community college students more likely to vote in an election year when the President of the United States will be chosen?

Q6) For each of the following research questions, determine whether an observational study, an experiment, or neither should be used to answer the question. Note - each term on the right may be used more than once or not at all.

Group of answer choices

• What proportion community college students successfully complete transfer-level English course?

• Are non-elite soccer players less likely to develop arthritis of the hip or knee than elite soccer players?

• Does shifting flora and fauna to new habitats lead to the extinction of some species?

• Does consumption of simple carbohydrates increase the oxidation of LDL cholesterol?

Q7) Hospital floors: Hospital floors are usually bare tiles instead of carpet. Carpets will decrease noise but might increase germ growth.

To study this, researchers installed carpet in 8 of 16 hospital rooms. They randomly selected the rooms to carpet. The other rooms had bare tiles.

After two weeks of normal use, they collected air samples from the rooms and counted the bacteria in each sample.

To identify the explanatory and response variables, match each of the following with one of the terms on the right. Note - any given term may be used more than once or not at all.

Group of answer choices

• Air samples

• Type of floor covering

• Hospital rooms

• Bacteria count

Q8) Energy Drinks: Popular energy drinks contain green tea extract and caffeine. Do these energy drinks help you lose weight by increasing your metabolism?

Researchers at a medical school designed an experiment to determine the effects of green tea and caffeine on energy metabolism in healthy, lean, young adults.

Researchers randomly assigned participants to 2 treatments. One group drank Formula A, a beverage with green tea and caffeine. The other group drank Formula B, a beverage with none of these ingredients but colored to look like Formula A. The beverages were blinded at the production site, so the experiment was double-blind.

The researchers chilled the beverages to 6C. Participants drank the beverages at the same time each day for three days. During the 3 days of the experiment, the researchers feed each participant the same diet. On the 3rd day participants spent 24 hours in a calorimeter chamber to measure their energy metabolism. The medical journal Obesity published the results in 2007.

Which of the following is an example of direct control used in this experiment? Check all that apply.

Group of answer choices

Drinking the beverages at the same time each day

Mixing green tea and caffeine

Feeding each participant the same diet

Q9)

In its January 25, 2012, issue, theJournal of the American Medical Association(JAMA) reported on the effects of overconsumption of low, normal, and high protein diets on weight gain, energy expenditure, and body composition. Researchers conducted a single blind, randomized controlled trial of 25 U.S. adults. The subjects were healthy, weight-stable, male and female volunteers, aged 18 to 35 years. All subjects consumed a weight-stabilizing diet for 13 to 25 days. Afterwards, the researchers randomly assigned participants to diets containing various percentages of energy from protein: 5% (low protein), 15% (normal protein), or 25% (high protein). The subjects were not aware of the specific protein level diet to which they were assigned. On these diets the researchers overfed the participants during the last 8 weeks of their 10 to 12 week stay in the inpatient metabolic unit. The goal was to investigate the effect of overconsumption of protein on weight gain, energy expenditure, and body composition.

What is the purpose of random assignment in this experiment?Check all that apply.

Group of answer choices

To generalize the experiment results to a larger group

To avoid bias

To produce treatment groups with similar characteristics

To control for confounding variables