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.
X = Midpoint f = Frequency
To find the Arithmetic Mean of
| Intervals | Frequency(f) |
|---|---|
| 10 - 20 | 3 |
| 20 - 30 | 9 |
| 30 - 40 | 5 |
Find Σf. Σf = 17
Then, Find the Midpoint for the class interval. Midpoint(X) = (10+20)/2, (20+30)/2, (30+40)/2 = 15, 25, 35
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 |
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.
This tutorial will help you dynamically to find the Class Interval Arithmetic Mean problems.
