$A\frac{M}{M}\frac{?}{1}$ queue:

$=$ the average number $of$ arrivals per time period $(mean$ arrival rate$)$

$\frac{1}{}=$ the average time between arrivals

$=$ the average number $of$ services per time period $(mean$ service rate$)$

$\frac{1}{}=$ the average time taken for each service

$P_0=1-\frac{}{}$ the probabilit $y$ that $no$ units are $in$ the system

$L_q=\frac{{}^2}{(-)}$ the average number $of$ units $in$ the waiting line

$L=L_q+\frac{}{}$ the average number $of$ units $in$ the system for $\frac{M}{M}\frac{?}{1}$ case