After editing the written results(mp3) are larger in size

[bonzadog]

Using Audacity 1.3.7 , I edited an audio MP3 file and cut some chunks out. I then wrote the file (via Export) and a good mp3 file was created. However the generated file is much larger in size than the original input file. So no compression is taking place. I checked the options for any possible changes but did not find anything.

[steve]

Using Audacity 1.3.7 , I edited an audio MP3 file and cut some chunks out. I then wrote the file (via Export) and a good mp3 file was created. However the generated file is much larger in size than the original input file. So no compression is taking place. I checked the options for any possible changes but did not find anything.

<<< So no compression is taking place.>>> There probably IS compression taking place, but LESS than the original MP3.
To check if compression is happening, Export as a WAV file and compare the size.

You can adjust the amount of MP3 compression by clicking on the "Options" button.
For good quality stereo music, the "Standard" preset is a good option.
128kbps is generally considered the maximum amount of compression for good quality stereo music.
For mono files you can compress files a lot more - 64kbps (CBR) for a mono file is only marginally lower sound quality than 128kbps for a stereo file, but produces files that are only half the size.