A dot written next to a note, placed just to it's right, increases its duration or length by 50%. The dotted note is held for it's original length plus half again it's original length. A quarter note equals one beat in 4/4 time. Half of a quarter note equals an eighth note. One quarter note plus one eighth note, which is half its length, equals is 1 and 1/2 beats. If an eighth note equals half a beat and two eighth notes equal one quarter note, then a dotted quarter note equals 3 eighth notes in length or duration.
The same logic applies to eighth notes and sixteenth notes. By breaking the one "beat" of a quarter note down into even smaller increments than two eighth notes we'll create shorter notes called sixteenth notes. There are 4 sixteenth notes in a quarter note. Remembering that there are two eighth notes in a quarter note, we can see that there would be four sixteenth notes in a quarter note if we were to subdivide the beat further. There would be two sixteenth notes in each of the two eight notes of this quarter note. When a dot is placed to the right of an eighth note, (which can be broken down further into two sixteenth notes), we add to it's length or duration 50% of the value of the original eighth note. Half of an eighth note would be a single sixteenth note because there are two sixteenth notes in each eighth note. Therefore, a dotted eighth note equals the held length of three sixteenth notes.
When playing your bass and sustaining or "holding" this dotted eighth note for three sixteenth notes, there will be one sixteenth note left unaccounted for in the subdivided grouping of four sixteenth notes. Striking another note on that last subdivision of time, the final sixteenth note of the group of four, will produce a staccato 16th note as the fourth sixteenth in the subdivision of the four sixteenth notes per each beat. The effect is a longer note, held for three sixteenth notes, and a short note, held for one sixteenth note, within one beat of time in the groove. The last sixteenth of the grouping of four is said to "anticipate" the next downbeat of the groove!