| 摘要 |
A statistical sampling apparatus is formed with a box-like enclosure having transparent top, front and bottom walls. A stationary ledge extends in a plane between the top and bottom wails and stops short of the front wall so that there is a space that communicates between the volume below the ledge and the volume above the ledge. A plurality of identically shaped beads are disposed within the enclosure. The upper surface of the ledge has a patterned array of identical recesses which receive certain of the beads when the enclosure is up-ended and the beads are allowed to wash over the ledge. The beads are of different colors in a known distribution, and the patterned array of recesses is divided into series of a smaller numbers of recesses for statistical sampling purposes.
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