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define the term "Biased"
not 100% reliable, slanted to promote position, facts that support a predetermined opinion
define the term "unbiased"
reliable, fair and thorough, seeking truth
what are red flags of nutrition?
statements that sounds to good to be true
what are some examples of red flags of nutrition quakery
- "one product does it all"
- "satisfaction guaranteed"
- "quick and easy fixes"
define scientific method
research begins with a question, then it systematically conducts studies to collect data that will test the hypothesis
what is a variable?
a factor that changes
what is positive correlation?
the simultaneous increase or decrease in two variables. if A increases then B increases
what is a negative correlation?
the simultaneous decrease of two variables, if A decreases then B decreases
what is the difference between correlation and cause and effect
correlation proves only that variables are associated but does not prove cause and effect
what are the 2 general types of studies?
which studies can only show correlation?
epidemiological studies such as cross-sectional, case-control and cohort studies
which studies show cause and effect?
experimental studies such as laboratory animal/human studies and human intervention/clinical studies
define epidemiological studies
compares variables, shows only correlation not cause and effect. no experiment is done, people are not asked to take anything or stop taking something. There is no control factors
what are the 3 sub studies in Epidemiological studies?
1-cross sectional studies
2-case controlled studies (retrospective)
3-cohort studies (prospective)
define cross sectional studies
researchers observe how much and what kinds of food a group of people eat and how healthy those people are, findings ID factors that might influence the incidence of a disease in various populations.
Example is mediterranean people drink more wine and more fat from olive oil and have a lower incidence of heart disease
define case controlled study
researchers compare people who do and do not have a given condition such as a disease. It closely matches them in age, gender and other key variables. Research tends to be retrospective.
Example is people with goiter lack iodine in their diets
define cohort studies
researchers analyse date collected from a selected group of people (a cohort) at intervals over a period of time. studies follows people- looking at the future.
example is data collected over several decades reveals that the risk of heart attacks increase as blood cholesterol increases
define experimental studies
subjects do something (change a variable) and a variable is measured before and after they do something. everything is the same except what you changed.
define laboratory based studies
studies explore the effects of a specific variable on a tissue, cell or molecule. Often conducted in test tubes or on animals. It can determine effects of a variable but cannot apply results on animals or human beings
what are the 3 sub studies in experimental study?
1- laboratory based animal studies
2-laboratory based in vitro studies
3-human intervention or clinical trials
define laboratory based animal studies
researchers feed animals special diets that provide or omit specific nutrients and observe any changes in health
example is a mice fed high-fat diets and another a low fat diet with same Kcals but mice with high fat diet is severely obese
define laboratory based in vitro studies
researchers examine the effects of a specific variable on a tissue, cell or molecule isolated from a living organism.
example is fish oils inhibit the growth and activity of bacteria implicated in ulcer formation
define human intervention/clinical trials
people are asked to adopt a new behavior that can help determine the effectiveness of such interventions on the development or prevention of disease
example is heart disease factors improve when men receive fresh squeezed OJ compared with those on a diet low in vitamin C
what needs to be controlled for a valid experimental study?
the variable that has been changed
why is a control group needed in experimental study?
because it proves cause and effect. It shows the controlled variable is responsible for the effects of the experiment
what is the placebo effect?
the power of belief, a change that occurs in response to expectation about the effectiveness of a treatment that actually has no pharmaceutical effects
how is the placebo effect controlled in a experimental study?
give pills to all participants
what is a placebo?
an inert harmless medication given to provide comfort and hope. A sham treatment.
what is "investigator bias?"
investigator bias is an unfair, unreliable conclusion that benefits the investigor
how is investigator bias controlled in a experimental study
by having a third party code the pills and not revealing to the experimenters who belongs to the experimental or controlled group
what is anecdotal evidence?
a personal account of an experience or event
why does anecdotal evidence not support nutritional claims?
because it has not scientific proof of its effects
define single blind experiment
an experiment where subjects do not know whether they are members of the experimental group or the controlled group
define double blind experiment
an experiment where neither the subjects nor the researchers know which subjects are the experimental or controlled group
what does single blind experiment control?
the placebo effect
what does a double blind experiment control?
the placebo effect and experimenter bias
what is gold standards for experimental research?
the most accurate test possible without restrictions. gold standard test refers to a diagnostic test that is the best available under reasonable conditions.
define peer review
a process is which a panel of scientist rigorously evaluate a research study to assure that the scientific method was followed
define peer review journal
an academic periodical publication
how is peer review journal different than a popular magazine?
peer review is evaluated by other scientist and popular magazines are evaluated by editor who makes sure publication will yield economic gains