Hannah has developed a scale for assessing social interaction among children with moderate to severe developmental disabilities. because it is in the early stages, she trains two research assistants in how to use the scale, has them both observe the same children, and compares the scores they give the children. hannah is assessing reliability.

internal consistency                                                  

Explanation:

Internal consistency reliability: It defines the proficiency of an item to measure the same idea or construct. It is the most widely used reliability method. It plays a significant role when the researcher wants to make sure that they have incorporated a desired number of items to apprehend the concept adequately. Few items will be sufficient for a narrow concept.

Internal consistency reliability is defined as the consistency across items.

Hence, Hannah is assessing internal consistency reliability.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."

answer; through play and social interaction;