Question

mr. li records the measures of the lengths of his students handprints. the lengths, in centimeters, are shown in the table.

14.0	11.5	12.1	16.2	13.5	14.3	16.8
12.4	13.7	12.0	14.7	15.2	11.9	15.6
13.8	14.2	12.5	15.0	16.0	13.1	11.7

if the class creates a histogram of the data in the table, how many students are in the range 12 cm to 13.9 cm?

○ 3
○ 4
○ 7
○ 8

Explanation:

Step1: Identify data in range

We need to find all the handprint lengths (in cm) that are greater than or equal to 12.0 and less than 13.9. Let's list out the data points from the table:

• From the first row: 14.0 (no), 11.5 (no), 12.1 (yes), 16.2 (no), 13.5 (yes), 14.3 (no), 16.8 (no)
• From the second row: 12.4 (yes), 13.7 (yes), 12.0 (yes), 14.7 (no), 15.2 (no), 11.9 (no), 15.6 (no)
• From the third row: 13.8 (yes), 14.2 (no), 12.5 (yes), 15.0 (no), 16.0 (no), 13.1 (yes), 11.7 (no)

Step2: Count the valid data points

Now let's count the "yes" ones: 12.1, 13.5, 12.4, 13.7, 12.0, 13.8, 12.5, 13.1. Wait, let's list them again carefully:

First row valid: 12.1, 13.5 (2)
Second row valid: 12.4, 13.7, 12.0 (3)
Third row valid: 13.8, 12.5, 13.1 (3)

Wait, let's check each number:

12.1 (yes), 13.5 (yes), 12.4 (yes), 13.7 (yes), 12.0 (yes), 13.8 (yes), 12.5 (yes), 13.1 (yes). Wait, that's 8? Wait no, let's list all numbers in the table and check:

All data points:
14.0, 11.5, 12.1, 16.2, 13.5, 14.3, 16.8,
12.4, 13.7, 12.0, 14.7, 15.2, 11.9, 15.6,
13.8, 14.2, 12.5, 15.0, 16.0, 13.1, 11.7

Now filter those with \( 12.0 \leq x < 13.9 \):

12.1 (12.1 is between 12 and 13.9), 13.5 (yes), 12.4 (yes), 13.7 (yes), 12.0 (yes), 13.8 (yes), 12.5 (yes), 13.1 (yes). Wait, let's count:

12.1, 13.5, 12.4, 13.7, 12.0, 13.8, 12.5, 13.1. That's 8? Wait no, let's check each:

12.1: yes (12 ≤ 12.1 <13.9)
13.5: yes
12.4: yes
13.7: yes
12.0: yes
13.8: yes
12.5: yes
13.1: yes

Wait, that's 8? Wait the options are 3,4,7,8. So 8? Wait maybe I made a mistake earlier. Let's list all numbers in the range:

From the first row: 12.1, 13.5 (2)
Second row: 12.4, 13.7, 12.0 (3)
Third row: 13.8, 12.5, 13.1 (3)
Total: 2+3+3=8. Yes, that's 8.

Answer:

8