What ways to psychologist gather information

The most common techniques used to collect data for case studies are:
personal interviews.
direct observation.
psychometric tests.
archival records. I hope i have helped:)

Questionnaires, surveys and checklists.

Personal interviews.

Documentation review.

Observation.

Focus group.

Case Studies

Explanation: This process not only allows scientists to investigate and understand different psychological phenomena, but it also provides researchers and others a way to share and discuss the results of their studies.

The most credible way to cite the information is, "Anderson argues that the characters represent "the essential American couple" (24).

This is the most credible because it states the name of the author and is written in a way that is grammatically correct and without adding extra information. The other sentences are not the best for the following reasons:

A new book argues that the characters are "the essential American couple" (24).

It does not state the author, which makes the citation less credible.

Anderson's new book claims these characters are "the essential American couple," and others agree."

This sentence starts off okay, but the ending "and others agree" cannot be proven which makes it less credible.

"The essential American couple is prototyped in these characters," writes Anderson in his recent book."

This sentence is not properly cited as it does not have a page number, but it is also written in a way that makes it harder to understand for the reader.