Which will NOT help control for extraneous variables?

Which will NOT help control for extraneous variables?
 
  a) using a control group
  b) randomization
  c) matching of subjects
  d) using homogenous groups

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What is the most serious threat to internal validity in nonequivalent control group design?
 
  a) selection
  b) maturation
  c) mortality
  d) testing

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What is the first step in conducting historical research?
 
  a) evaluating authenticity and accuracy of evidence
  b) formulating a hypothesis
  c) defining a topic or problem
  d) integrating data

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__________ is a statement about the relationship between variables.
 
  a. Categorization
  b. Association
  c. Correlation
  d. Hypothesis

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When you cannot use a pretest, what would be the appropriate design to use?
 
  a) nonequivalent control group design
  b) static group comparison
  c) single-subject design
  d) ABAB design