Question

a teacher records the test scores for the students in her class. the results are shown in the box plot below. students test scores based on these data, what is the interquartile range? a 3 b 8 c 11 d 21

Explanation:

Step1: Identify Q1 and Q3 from box plot

From the box plot, the first quartile (Q1) is at 67 (since each tick is 1 unit, starting from 60, Q1 is at 67) and the third quartile (Q3) is at 78 (Q3 is at 78). Wait, actually, looking at the plot, let's re - check. The box starts at Q1 and ends at Q3. Let's see the scale: from 60 to 85, each small tick is 1. The left end of the box (Q1) is at 67? Wait, no, maybe I misread. Wait, the box plot: the first quartile (Q1) is the left edge of the box, and the third quartile (Q3) is the right edge of the box. Wait, looking at the plot, let's count the ticks. From 60, each tick is 1. Let's see: the left whisker starts at 62? No, wait the first vertical line (minimum) is at 62? Wait, no, the leftmost line (minimum) is at 62? Wait, no, the box starts at Q1. Wait, maybe the correct Q1 is 67 and Q3 is 78? Wait, no, let's do it properly. The interquartile range (IQR) is Q3 - Q1. Wait, maybe the Q1 is 67 and Q3 is 78? Wait, no, looking at the options, let's re - evaluate. Wait, maybe the Q1 is 67 and Q3 is 78? No, wait the options are 3,8,11,21. Wait, maybe I made a mistake. Wait, let's look at the box plot again. The left edge of the box (Q1) is at 67, the right edge (Q3) is at 78? No, 78 - 67 = 11. Oh, that's option C. Wait, let's confirm: IQR = Q3 - Q1. If Q1 is 67 and Q3 is 78, then 78 - 67 = 11. So that's the IQR.

Step2: Calculate IQR

IQR = Q3 - Q1. Let's assume Q1 = 67 and Q3 = 78 (from the box plot). Then IQR = 78 - 67 = 11.

Answer:

C. 11