Do as Ginosaji suggests, for a while--an hour or more. CRTL-C see what your statistics are, if you're a zombie you're welcome to watch this as well. This is to determine if you have a general connection issue or not. Having the best internet services means nothing, with cable you could have an issue with your modem, the wiring, or the connection outside. As seasons change where I live, it's not uncommon for moisture to become an issue--sometimes a line tech has to come out and pretty much just disconnect/reconnect my line from the pole to the house.
If you have other people using your connection in your household this can give you packetloss/ping spikes as well.