Which of the following could constitute a sampling frame?

Which of the following could constitute a sampling frame?
 
  a. A single-subject design intended to test the efficacy of Parent EffectivenessTraining.
 b. A pretest of an experiment.
  c. The results of a study that have been reported in a human service journal.
  d. A list of all clients of a community mental health agency.

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In drawing samples, the overriding consideration is that the samples ________ the population from which they are drawn.
 
  a. be quite different from
  b. contain all the same units of analysis as
  c. be representative of
  d. be pretests of

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One of the advantages of the multiple forms method of assessing reliability is
 
  a. it can be used when the measuring device consists of only one item.
  b. it cannot be used if the values of variables change over time.
  c. only one testing session is required. d. it incorporates a control group into the reliability design.