Can someone me with this question?

I sort the data from the lowest
17.7, 18.3, 19.2, 21.1, 21.7, 23.2, 23.4, 23.7, 25.8, 26.2, 27.3, 27.4, 29.4, 29.8, 31.6, 33.5, 37.7, 38.9, 44.9

Then I classify the data to the appropriate class
1) Class 15.0-20.9
There are 3 data, those are 17.7, 18.3, and 19.2
2) Class 21.0 - 26.9
There are 7 data, those are 21.1, 21.7, 23.2, 23.4, 23.7, 25.8, 26.2
3) Class 27.0 - 32.9
There are 5 data, those are 27.3, 27.4, 29.4, 29.8, 31.6
4) Class 33.0 - 38.9
There are 3 data, those are 33.5, 37.7, 38.9
5) Class 39.0 - 44.9
There is 1 data, that is 44.9

SUMMARY
BMI Class and frequency
15.0 - 20.9  ⇒ frequency 3
21.0 - 26.9  ⇒ frequency 7
27.0 - 32.9  ⇒ frequency 5 
33.0 - 38.9  ⇒ frequency 3
39.0 - 44.9  ⇒ frequency 1