Question 3 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 whether 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 4 5 3 0 0 5 0 0 0 5 0 5 1 5 5 0 Teachers 2 0 1 5 1 5 1 0 1 0 0 5 0 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 tend to have watch times that are closer to the true time Explain your choice c The teacher wants to know whether individual students watches tend to be set correctly She proposes to test H u 0 versus H 0 where u represents the mean amount by which all student watches differ from the correct time Is this an appropriate pair of hypothesis to test to answer the teacher s question Explain why or why not Do not carry out the test