Standard deviation is the square root of variance, but variance is given by mean, so divide by number of samples. That is : 38.5/10 = 3.58. But standard deviation equals the square root of variance, so SD = the square root of 3.85 which is 1.96.
The virginal(s): The virginal, also called virginals, usually has a rectangular case with the keyboard across the wide side. As with the spinet, the strings run side-to-side relative to the player. Again, it saves on wallspace, and again they rate their own FAQ. Virginals were fairly early, 15th and16th centuries.
Despite the uncertainty regarding the eschiquier, it seems probable that the clavichord was the earliest stringed instrument having keys that could be pushed down by the fingers. The term âclavichordâ first appears in a German document from 1404, and the instrument is recognizable in a German altar carving from 1425.