The picture is part one of the question. Part 2 of this question is the following : the brackets or error bars shown at the top of each bar extend (either one standard error or one standard deviation)- please pick one that is correct to complete that sentence.

A researcher is investigating whether a reading intervention program improves reading comprehension for second graders. He collects a random sample of second graders and randomly assigns each second grader to participate in the reading Intervention program or not participate in the program. The researcher knows that the standard deviation of the reading comprehension scores among all second graders is o = 13.35. ools Group 1 consists of ns = 38 second graders who did not participate in the program. Their mean reading comprehension score is Ma = 22.8, Group 2 consists of nz = 42 second graders who did participate in the program, Their mean reading comprehension score is Ma = 46.1. Of the plots that follow, which best represents a plot of these results? O Plot B O Plot A O Plot C O Plot D Plot A Plot B 20 10 Plot C Plot D 20 TO group 2 here to search