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).
The musical scene in the classical period reflected the changes occurring in the society in which the music was being written. This was the first era in music history in which public concerts became an important part of the musical scene.