A researcher trains observers to complete checklists while observing children's behavior on the schoolyard during recess. Over the course of the study, observers become more reliable in their observations. Any effect of a treatment in this study might be confounded with an threat to internal validity.

expectancy effect

Explanation:            

Expectancy effect: In psychology, the term "expectancy effect" is described as the result that an experimental observer or researcher tends to generate when he or she is somehow, subconsciously or subtly, transmitted the "expected results" related to the participant.

In other words, it represents the subconscious effect of an experimenter on the test or study participants.

In the question above, the given statement signifies the expectancy effect.

the correct answer is option c. elenita versus "early puerto rican decor" is the best example, out of all the options, of a cultural conflict. a cultural conflict is defined as what happens when different cultures, that have different values and believes, clash. elenita not liking or accepting the puerto rican style of decoration, would represent that she does not identify herself with the puerto rican culture, therefore does not want to have decorations influenced by that culture.

answer; the government can clearly justify the restriction;