A student investigates how well a wooden partition insulates against different frequencies of sound. They measure the transmitted sound level in decibels (dB) for several frequencies.
| Frequency (Hz) | Transmitted Sound Level (dB) |
|---|---|
| 125 | 72 |
| 250 | 65 |
| 500 | 58 |
| 1000 | 38 |
| 2000 | 45 |
| 4000 | 52 |
State the reason why 1000 Hz is identified as the frequency at which the partition is the most effective sound insulator.