A difficulty in studying residential treatment programs for drug ...

[jilianpiloj]

A difficulty in studying residential treatment programs for drug abuse is that
 
  a) most residences are secretive and unwilling to allow research activity.
  b) addicts at such settings are not severely addicted.
  c) patients at these settings are voluntary, and therefore these addicts represent a minority of the actual addict population.
  d) the number of patients entering such settings changes slowly, making it difficult to obtain an adequate number of participants.

Question 2

Approximately how much of the sleep of an adult is spent in stage 2 sleep?
 
  a) 10
  b) 25
  c) 50
  d) 75

[Christopher]

Answer to Question 1

c

Answer to Question 2

c

[jilianpiloj]

TYSM

[chereeb]

Gracias!