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STT Exam 1 Questions and Answers (100%
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Explanatory variable Ans: - The variable that is manipulated by
researchers
- The variable that is thought to cause a different in an outcome
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Response Variable Ans: - The variable that is observed by researchers
- The variable that 'answers' the research question
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In the early 1950's there was limited evidence that a vaccine developed
by Jonas Salk was both safe and effective, based on small studies. A
large-scale trial was needed to assess the effectiveness of the vaccine.
What is the explanatory and response variable? Ans: Explanatory: If you
get the vaccine or not
Response Variable: Immune response to polio/do you get it or not
Treatment Group Ans: The group of subjects in a study that receives a
treatment
Control Group Ans: A separate group of subjects in a study that does
not receive the treatment
Confounding Factors Ans: hidden variables that correlate in some way
with the independent or dependent variable and have some sort of
impact on the results; threat to internal validity - Consent EX
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How to decrease confounding factors Ans: Randomizing the assignment
makes the treatment and control group approximately the same with
respect to all variables except for the explanatory variable (treatment)
and decreases the influence of confounding factors
Placebo Effect Ans: the phenomenon in which the expectations of the
participants in a study can influence their behavior
Double-Blind Study Ans: An experiment in which neither the participant
nor the researcher knows whether the participant has received the
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treatment or the placebo
What does a double-blind study alleviate? Ans: Possible bias in diagnosis
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To identify the explanatory variable in a pair of variables, identify which
of the two is suspected of affecting the other? Ans: Explanatory variable
— might affect — response variable
Generally, data in observational studies are collected only — while
experiment require the primary explanatory variable in a study — for
each subject by the researchers Ans: - by monitoring what occurs
- be assigned
Making casual conclusions based on experiments is often resonable.
However, making the same casual convulsion based on observational
data can be treacherous and is not recommended. Thus, observational
studies are generally only sufficient... Ans: to show associations
Casual Relationship in Stats Ans: Observational Studies: Don't do it!!