What is true about extraneous variables? correct answers They only trick the researchers into misinterpreting the results when they relate to both the independent variable and the dependent variable.
A researcher studies the relationship between consumption of fructose and diabetes. The research...
BBH 310 Final Exam || Already Passed.
What is true about extraneous variables? correct answers They only trick the researchers into
misinterpreting the results when they relate to both the independent variable and the dependent
variable.
A researcher studies the relationship between consumption of fructose and diabetes. The
researcher has three variables about each participant: how much fructose the person usually eats
(estimated from surveys about the person's typical diet), the person's age, and diabetes status
(whether the person says they have been diagnosed with diabetes or not). The researcher
hypothesizes that consumption of fructose causes a fatty liver which screws with some hormones
that then leads to insulin resistance which then progresses to full blown diabetes. The researcher
finds that age is associated with risk of diabetes (older people are more likely to have diabetes)
but not with fructose intake (people of all ages have similar fructose intake). Based on these
results, age is likely correct answers Not a confounder because it is not related to the predictor
A popcorn salesman/amateur researcher studies the effects of watching funny movies on fatigue
by surveying people on their energy level as they walk out of the movie theater on a scale of 1-
10, depending on whether the movie was a comedy or a different type. He thinks a good laugh
will reinvigorate the psyche and dispel fatigue. However, he is concerned about time of day
effects--while he was collecting data, the comedies tended to more often be earlier in the day
than the non-comedies. Also, as expected, fatigue does change with time of day. Thus, time of
day is correct answers A confounder
Researchers investigate the correlation between height (tallness) and blood estrogen levels. They
analyze their data two different ways, first including all people in their sample (both genders)
and second including only women. The first results show a significant correlation between height
and estrogen levels (taller people have lower estrogen). The second results show no significant
correlation between height and estrogen levels. They report that gender is a confounder that is
_____ the association between height and estrogen levels. correct answers Exaggerating
Imagine that we have two studies investigating the effects of a therapy on an outcome, one that
allows people to volunteer for the therapy (so it's really more of an observational study) and one
that is truly experimental (a randomized clinical trial). What type of confounder is consistently
more of a problem in the observational design than the randomized clinical trials? correct
answers Unequal distribution of demographic variables between the individuals who receive the
treatment and the individuals who don't
Imagine that researchers conduct a cohort study, following children from early life to adulthood.
Researchers recruit one randomized sample of kids from a school district, ask them many
questions about their screen time, and then monitor whether or not they develop obesity over the
next few years. The researchers find that there is some attrition from the group - each year, some
students move away and live in different places. They find that attrition is more common among
children with more screen time, compared to among children with less screen time. They find
that attrition is not correlated with body weight. In this study, attrition is correct answers Not a
,confounder of the association between screen time and body weight because it is not related to
the outcome
Researchers compare an exercise intervention to an education-about-exercise-but-no-actual-
exercise control group. They measure outcomes at the end of each session of exercise or each
classroom activity depending on which arm of the trial it's in. The exercise is done in a gym,
while the education group goes to a classroom. Since the researchers are doing random
assignment to the exercise intervention and using the control group, they plan to interpret the
differences in the outcomes as being caused by the intervention. However, they should watch out
for which confounders? correct answers Differences in expected benefits and also differences
that may relate to the different settings between the groups
A researcher is interested in examining the negative effect of chocolate consumption on
cardiovascular risk, based on the high sugar and fat content of most chocolates. She decides that
Easter, a time of increased chocolate consumption, is the perfect time to test this. She tests
cardiovascular risk markers in her participants both 2 days before and 2 days after Easter, and
asks for reports about how much chocolate-based easter candy participants ate. Contrary to her
hypothesis, she does not find a greater decrease in cardiovascular health among individuals who
reported eating more chocolate. A colleague of her points out that chocolate contains flavonoids,
which might benefit cardiovascular health. In this researcher's study, flavonoids represent correct
answers A confound
Randomized clinical trials testing specific psychotherapy and behavioral interventions are almost
always confounded by correct answers Expectation effects
A researcher studies whether a therapy works for reducing blood pressure. Aging is the single
largest risk factor for high blood pressure, so it's important to make sure that age is not a
confounder in the study. What is the most appropriate way for the researcher to handle this
issue? correct answers Control for age statistically, using statistical analysis to balance out age
effects
Case- control studies differ from cross- sectional studies because they correct answers don't have
the same sampling procedures for all participants
Both designs are the same, neither one has a randomized control group, neither design collects
data from each participant at 2 or more time points and both designs can ask as many questions
as they want correct answers comparisons of case- control studies and cross- sectional studies.
Case- control studies correct answers recruit two groups two ways
Cross- sectional studies correct answers recruit one group in one big sampling process
What study design would not make sense to use random sampling? correct answers case study
, Cohort studies are a much better choice than case- control studies when the predictor__________
and the outcome is relatively__________( choose the option where the advantage of cohort
studies over case- control are most extreme) correct answers Hard to remember correctly, rare.
Identify the study design. Lee et al. (2015) write: "we aimed to determine whether changes in
metabolic health status or obesity OVER TIME have any effect on the risk of future diabetes.
non diabetic individuals (n=2692) from a study with baseline and 2 follow-up examinations at 4-
year intervals were included. Individuals were classified as "obese" or "non obese" using a body
max index of 25 kg/ m2 as a cut off. The risk of diabetes at year 8 was assessed according to
changes of metabolic health status were an independent risk factor for future diabetes in non
obese individuals, whereas general obesity had a greater contribution to the risk of obese
individuals developing diabetes." correct answers cohort study
A group of BBH 411W students put together a set of questions and we email it out to students in
BBH 310. What is the research design for this project? correct answers cross- sectional
A research group collects saliva from people who are watching popular action movies during
their first showing. The researchers do not decide who shows up to the movies or what is the
content of the movies, they just recruit whoever shows up at whichever movies come out during
their study time frame. The test the hypothesis that testosterone will be elevated at the end of
movies where the hero "wins"/ survives and testosterone will be lower at the end of movies
where the hero dies a tragic death or fails on a major part of his / her mission. This design is a ?
correct answers cross- sectional
Gallup is an organization that does polls (brief survey studies) of different populations to ask
them questions about important issues of our day. Their goal is to figure out what people think.
In 2014, they found hat many Americans were worried about getting Ebola. This study is a ?
correct answers cross- sectional
What type of study is most suitable for studying risk factors for a very rare disease? correct
answers case- control
What reasons do observational studies have advantages over experimental studies correct
answers - you can study the effects of dangerous drugs of abuse
-you can study the effects of ethnicity
-you have fewer problems with the ethics of manipulating variables
Why is experiments better then observational studies correct answers you have fewer problems
with confounding variables
When we examine the link between a "person variable" and a health outcome, we would use an
"__________" design correct answers observational
case control studies differ from cross sectional studies because they? correct answers don't have
the same sampling procedures for all participants
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