In an experiment on the effects of massed versus distributed ...

[jparksx]

In an experiment on the effects of massed versus distributed practice on learning, introductory psychology students who volunteered for extra credit were randomly assigned to one of two groups.
 
  Both groups were to practice a perceptual-motor task five times for 10 minutes each. Group 1 did all five 10-minute practice sessions in one evening while group 2 was asked to do one 10-minute practice session a night for five consecutive nights. All of the participants in Group 1 completed the experiment, but only 30 of the participants in Group 2 showed up for all five nights. This study is an example of confounding by
   
 a. differential attrition.
  b. selection bias.
  c. history.
  d. demand characteristics.

Question 2

A metacrawler or meta search engine works by
 
  a. remembering your search history to allow more efficient searches in the future.
  b. submitting your search query to several different search engines and including all of the results.
  c. allowing you to research multiple topics in a single search.
  d. finding and storing new information related to your topic for days after your original search

[momo1250]

Answer to Question 1

A

Answer to Question 2

B