Extraneous variables a. tend to be problems in single blind ...

[kwoodring]

Extraneous variables
 
  a. tend to be problems in single blind studies, but not double blind studies.
  b. tend to reduce the degree of external validity in a study.
  c. can be avoided through random sampling.
  d. can sometimes be dealt with by using control groups.

Question 2

Survey researchers choose to use samples from a population rather than conducting a census because
 
  a. with large populations, you don't need to survey everybody in order to get a good depiction of what the population is like.
  b. it is impossible to get every member of any population.
  c. surveying a population typically leads to greater levels of response bias.
  d. respondents in a population are more likely to engage in optimizing than respondents in a sample.

[ankilker]

Answer to Question 1

D

Answer to Question 2

A