Answer:
I think the confidence interval formula in statistics is used to describe the amount of uncertainty associated with a sample estimate of a population parameter. It describes the uncertainty associated with a sampling method. To recall, the confidence interval is a range within which most plausible values would occur.
Explanation:
The instrument described is a clavichord.
Although not very popular nowadays, it was important between the 15th and the 19th century. In popular music, variations of it can be found in songs by artists such as Stevie Wonder and Bjork, but they mostly used the electric version of the instrument.