Complex sentence: First, only some fraction of dials are answered, For example, if 1 out of 3 dials are answered, a predictive dialer might dial 3 lines every time an agent becomes available.
Split into simpler sentences: First, only some fraction of dials are answered. So, for example, if 1 out of 3 dials are answered, a predictive dialer might dial 3 lines every time an agent becomes available.