What does it mean when a tool of assessment is characterized as reliable?

1. What does it mean when a tool of assessment is characterized as reliable? Under whatconditions might one expect an otherwise useful tool of assessment to be unreliable?2. Consider the meaning of the following statement: “A test is valid.” How absolute or relative is test validity? Can a test be valid at one time and place with one population of test takers and invalid at another time, in another place, or with another group of test takers?thread of at least 350 words must support your assertions with at least 1 scholarly citation and 1 scriptural citation in current APA format.