Question

Correct Formula to find
class interval

Answer 1

Lower limit + upper limit, whole divided by 2

Answer 2

Class Interval Mean Tutorial
Class Interval Arithmetic Mean Definition:
A range of values of a variable, an interval used in dividing the scale of the variable for the purpose of tabulating the frequency distribution of a sample. In other words, we can define as the individual group of scores in a grouped frequency distribution.
Formula: Class Interval Arithmetic Mean : Arithmetic Mean = ΣfX/Σf where
X = Midpoint f = Frequency

Class Interval Arithmetic Mean Example:
To find the Arithmetic Mean of
Intervals Frequency(f)
10 - 20 3
20 - 30 9
30 - 40 5
Step 1:
Find Σf.Σf = 17
Step 2:
Then, Find the Midpoint for the class interval. Midpoint(X) = (10+20)/2, (20+30)/2, (30+40)/2 = 15, 25, 35
Step 3:
Now, Find ΣfX. ΣfX =((3*15)+(9*25)+(5*35)) = (45+225+175) = 445
Intervals Frequency(f) Midpoint Xf
10 - 20 3 (10 + 20)/2 = 15 3 * 15 = 45
20 - 30 9 (20 + 30)/2 = 25 9 * 25 = 225
30 - 40 5 (30 + 40)/2 = 35 5 * 35 = 175
Step 4:
Now, Substitute in the above formula given. Arithmetic mean = ΣfX/Σf = 445/17 = 26.1765 This example will clearly illustrates how to calculate the Class Interval Arithmetic mean manually.
I hope the answer had helped u