Sun mi is designing a questionnaire on loneliness. she is concerned that some features of loneliness are similar to depression and to low self-esteem. what type of validity does she need to show to demonstrate that her questionnaire assesses loneliness and not depression or low self-esteem?

The type of validity that needs to be shown here is Discriminant Validity.

Discriminant validity is the degree to which two conceptually similar concepts are distinct. In other words loneliness and depression have similar traits and might appear to be the same in terms of what is being measured in a questionnaire but they are in fact unrelated concepts and this needs to be addressed when creating and using questionnaires.

hello,

your answer is ready

i believe its either the first or third option but i'm leaning more towards the third option:

the first excerpt makes a logical appeal, while the second excerpt makes an emotional appeal.

your pal

~papaguy