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.
The vibraphone (also known as the vibraharp or simply the vibes) is a musical instrument in the struck idiophone subfamily of the percussion family. The vibraphone resembles the xylophone, marimba, and glockenspiel. Each bar is paired with a resonator tube that has a motor-driven butterfly valve at its upper end.