yakni . . .
| Nilai | Frekuensi |
|---|---|
| 40 – 44 | 1 |
| 45 – 49 | 2 |
| 50 – 54 | 3 |
| 55 – 59 | 6 |
| 60 – 64 | 7 |
| 65 – 69 | 5 |
| 70 – 74 | 7 |
| 75 – 79 | 9 |
Pembahasan
| Nilai | Frekuensi | xᵢ | fᵢ.xᵢ |
|---|---|---|---|
| 40 – 44 | 1 | 42 | 42 |
| 45 – 49 | 2 | 47 | 94 |
| 50 – 54 | 3 | 52 | 156 |
| 55 – 59 | 6 | 57 | 342 |
| 60 – 64 | 7 | 62 | 434 |
| 65 – 69 | 5 | 67 | 335 |
| 70 – 74 | 7 | 72 | 504 |
| 75 – 79 | 9 | 77 | 693 |
| Σ | 40 | 2600 |
xᵢ = nilai tengah pada interval ke-i
fᵢ = frekuensi interval ke-i
n = banyak data
x̅ = Σxᵢ.fᵢ = 2600 = 65
n 40