How to calculate the upsampling rate (sample per symbol) for a recorded raw IQ .wav file?
It is a unit conversion. You have the sampling rate given, $F_s$, and it has units of $\frac{\text{samples}}{\text{second}}$. You also have the symbol rate, $F_{sym}$, and it has units of $\frac{\text{symbols}}{\text{second}}$. You are trying to figure out what is the $\frac{\text{samples}}{\text{symbol}}$ so it is this division:
\begin{align}
\frac{\text{samples}}{\text{symbol}} &amp;= \frac{ F_s }{ F_{sym} } \\
&amp;= \frac{ \big(\frac{\text{samples}}{\text{second}} \big)}{ \big(\frac{\text{symbols}}{\text{second}} 
\big) } \\
&amp;= \frac{\text{samples}}{\text{symbol}} \checkmark
\end{align}