If the mean of a dataset is 25 and its standard deviation is 1.6, then. 1  68% of the values in the dataset will lie between MEAN-1SD (25-1.6=23.4) and MEAN+1SD (25+1.6=26.6) 2  99% of the values will lie between MEAN-3SD (25-4.8=20.2) and MEAN+3SD (25+4.8=29.8).
For the first time, during the Classical period most of the important stylistic advances that occurred can be observed most clearly in the instrumental forms: the symphony, concerto, sonata, and in instrumental chamber music (e.g., the Beethoven string quartets).
In fact, the Classical period, as the term is used in the study of the history of classical music, comprises a time in which the style of the music of the Baroque period gave way to the style of the Classical period. Moreover, the music may be ancient, contemporary, or dated somewhere between the two extremes.