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
Looking at the first term we know it's the power times the base to the power of to the original minus one. (-3x×2)^(2-1) = -6x Then the second term would just be the leading coefficient 4.
