I Statistics is a branch of mathematics that deals with averages, distribution of numbers, etc. of a group of numbers. For example, in cricket, you know that a batsman has scored so many runs in each one day match. You want to know his overall performance in one-day matches. You sum up his individual scores and divide it by the number of one day matches he has played. This will give you the average of his performance in one day matches that he has played.
Statistics creeps into all walks of lives.
The sequence of change in signals at a road crossing also depends on statistical inputs. The volume of traffic in either direction, the time of the day, how far is the next signal, etc. In Mumbai, for example, the flow of traffic in the morning is more in the southern direction and in the evening, the flow of traffic is more in the northward directions. The traffic signal circuits have to be timed in such a way that such variations during the day are taken into account. The timing of the signal changes will depend on the statistical inputs.