Hi,

I'm reading the paper called: Differential expression analysis for sequence count data. in the part of model description they have mentioned that: "We assume that the number of reads in sample *j* that are assigned to gene *i* can be modeled by a negative binomial (NB) distribution,".

I don't understand why it can be modeled by a negative binomial?

Intuitively, negative binomial distribution is the probability distribution of independent trails for k successes.

Would someone elaborate more that, why their assumption are make sense?

But still, negative binomial has its own definition and its application scenarios. Why RNA-seq fits into the definition and the application scenarios?

Yes, he did not answer your question. :)