Q:

How can HISAT2/StringTie report decimal coverage values

I have performed RNA-seq analysis using HISAT2 & StringTie workflow suggested in: Transcript-level expression analysis of RNA-seq experiments with HISAT, StringTie and Ballgown.  
Some of the transcripts/exons have decimal coverage values (eg.,  1.1 or 2.59).   
My question is: How can these tools report decimal coverage?  If only half of the read overlaps exon will this exon have 0.5 coverage? 

A:

I suspect this is average coverage across the transcript or exon.  
Formula for average coverage:

Where:

N: number of reads mapping/aligning to your transcript/exon
L: average read length
T: Transcript/exon length

