I have problem understading and doing this AP prolem. Please help me explain it clearly so that I could understand it.

Question

Problem: Since Hill Valley High School eliminated the use of bells between classes teachers have noticed that more students seem to be arriving to class a few minutes late. One teacher decided to collect data to determine wheather the students' and teachers' watches are displaying the correct time. At exactly 12:00 noon, the teacher asked 9 randomly selected students and 9 randomly selected teachers to record the times on their watches to the nearest half minute. The ordered data showing minutes after 12:00 as positive values and minutes before 12:00 as negative values are shown in the table below.

Students -.5 -3.0 -.5 0 0 .5 .5 1.5 5.0
Teachers -2.0 -1.5 -1.5 -1.0 -1.0 -.5 0 0 .5

A) construct parallel boxplots using these data

B) Based on the boxplots in part (a), which of the two groups, students or teachers, tends to have watch times that are closer to the true time? explain you choice

C) The teacher wants to know wheather individual student's wathces tend to be set correctly/ She proposes to test H nought: mean equal o versus H alternative: mean cannot equal 0, where the mean represents the mean amount by which all student watches differ from the correct time. Is this an sppropriate pair of hypotheses to test to answer the teacher's question? Explain why or why not. Do not carry out the test.

what are boxplots?

there almost like intugures...i think ....dont listen to me!!!