I studied statistics as a second major, and the "bank teller" problem is classic (Wrote solution in SPSS! lol)
If you feel that you are always in the slowest line, then check what's in their carts.
Is there a bagger, or does the teller have to stop ringing/scanning and do the bagging also?
Do people have their wallets ready, credit/debit card, or a ton of coupons and bags of change? ;)
There are a lot of factors and always the outcome for efficiency should be 1 line, n tellers, not n lines, n tellers.
I've made similar observation in subway: sometimes there are two trains in the opposite direction before the train in my direction arrives.I never witnessed two trains in my direction before the opposite arrives. The inevitable conclusion is that the opposite direction has always shorter intervals. I believe this stems from some symmetry violation in the quantum world, which also causes the matter to be more abundant than antimatter in the universe, and immediate speedups of the lane I've just left in a traffic jam.
I always end up behind the person paying with pennies. Or with a check that they don't even start to make out until after the total is rung up. Or is arguing about expired coupons. Or wants their items rung up as three separate orders.
Bear Bibeault wrote:I always end up behind the person paying with pennies....
I've once had my shopping processed at a cash register which froze in the middle and had to be rebooted. Only last few items (not the entire shoping) had to be processed again. Took some five minutes to get the damn thing up and running again. Didn't know MS is into the cash register business too
he sneakingly pulled an item from the customer ahead and dropped that item, forcing the guy ahead to bend or reach down to get it. and thereby making an opening or chance for him to overtake, forcefully if needed. do until ahead==0.
Airline ticket counters, car rental firms, and banks moved to one line feeding many workers decades ago. Its a trivial queueing theory example. I have yet to see any grocery stores with one line for many checkouts. They usually don't have the space. A person with a shopping cart takes more space than a person in a bank, or ticket line.