What research methods do psychologists use

Please provide answers to the questions below:

1. What research methods do psychologists use?
2. How do psychologists establish cause-and-effect relationships in research studies?
3. Match each of the following research methods with its primary disadvantage:
   

   1. archival research	a. The researcher may not be able to generalize to the population at large
   2. naturalistic observation	b. People’s behavior can change if they know they are being watched
   3. survey research	c. The data may not exist or may be unusable.
   4. case study	d. People may lie in order to pre- sent a good image.

4. A friend tells you, “Anxiety about speaking in public and performance are negatively correlated. Therefore, high anxiety must cause low performance.” Is this statement true or false, and why?
5. A psychologist wants to study the effect of attractiveness on willingness to help a person with a math problem. Attractiveness would be the ___________ variable, and the amount of helping would be the ____________variable.
6. The group in an experiment that receives no treatment is called the __________ group.