Question

the histogram shows the heights of 21 students in a class, grouped into groups of width 5 inches. how many students had heights greater than or equal to 55 inches, but less than 70 inches? a 13 b 15 c 16 d 17

Explanation:

Step1: Identify relevant bars

We need to consider the bars for height intervals 55 - 60 and 60 - 65.

Step2: Read frequencies

The frequency of the 55 - 60 inches bar is 6, and the frequency of the 60 - 65 inches bar is 5.

Step3: Calculate total

Add the frequencies: $6 + 5=11$. But we also need to consider the part of the 50 - 55 bar that is included in our range. Since we want heights $\geq55$, we ignore the part of the 50 - 55 bar below 55. The total number of students in the range 55 - 70 is $6+5 + 4=15$.

Answer:

B. 15