We keep it in a climate-controlled case and we hardly ever move it, because with any sudden shock it could just crumble to dust.

我们一直把它保存在严格候变化的展示台里，几乎不曾移动过；因为任突然震动都可能使它瞬间崩溃，化为一地尘。

It can come from a control chart kept in production or from calculating the standard deviation from a large amount of production data (be wary of special causes).

它可以来自生产中保存的图， 也可以来自计算大生产数据的标准偏差（警惕特殊原因）。