Apsychologist develops a measure of self-esteem in order to study the variable of self-esteem. he then conducts a number of studies investigating the differences between candidates who score low and candidates who score high on self-esteem. he does so to devise an accurate method of studying self-esteem. in this case, the psychologist is trying to establish

In this case, the psychologist is trying to establish "construct validity" of the measure.

Construct validity is "how much a test estimates what it claims, or implies, to quantify.  

There are various distinctive estimates that can be utilized to approve tests, one of which is build legitimacy. Build legitimacy is utilized to decide how well a test estimates what it should quantify. As it were, is the test built in a way that it effectively tests what it professes to test? Construct validity  is normally confirmed by contrasting the test with different tests that measure comparable characteristics to perceive how exceptionally associated the two measures are.

a) which ethnic groups live in this community?

i just took test