Signal bars are only a visual representation of the 'level' of the radio signal between the mast and your device. They do not represent the speed of throughput.
However, saying that, if all things were the same then a higher signal quality should see a higher throughput than a low signal level, but there are many factors at play that will affect the throughput available - the bands in use, the amount of spectrum a provider owns in those bands, the load on the cell, backhaul capacity to the mast are just some of them