An old man in a crumpled suit sits by the door.
This is his favourite spot, whenever he visits the shopping centre. He has a clear view of customers coming and going. He’d never really left his days working as a biostatistician behind; marrying statistics and biological data. He’d spent most of his working life applying his expertise to help medical researchers draw conclusions about population data, using his knowledge to design, analyse and interpret observational and intervention studies. Now, in retirement, his balding head and two days growth of stubble belie his eminent past.
It had all been about making calculations based on optimal sample size, organizing data collection, the programming of surveys and off-line data collection forms for cellular devices, the comparison of groups using parametric tests, performing survival analysis with life tables, his preparation of summaries describing the methodologies and analytic techniques he had used, his independent review of the statistical reporting of results, the fine tuning of existing analyses based on reviewer feedback and, of course, his own submission of reports. Primarily, it was all about using medical data in relation to human biology and health. That was the target, but he preferred the journey.
He sits now, watching people coming in and going out. Three in and two out. The three entering are girls, all teenagers. The two leaving are a middle aged couple. He mentally groups them by the basics, such as gender, age, and in some cases he can categorize them by employment, income, and even housing and education. He feels his degree of interpolation and guesswork is pretty accurate. In the main, he is putting societal and cultural factors aside. He sticks mainly to the basics.
Occasionally, he is able to mentally review the silently gathered statistics when the main entrance to the centre falls silent. Today the place had been busy with shoppers exchanging places with others, those exiting and those entering. It was a kind of exchange, a swapping of ins and outs, an ongoing interchange, a random pattern of movement, an endless to and fro of human traffic. It was a kind of unspoken reciprocal agreement between shoppers.
Five in and one out. The five were in two groups; mum, dad and daughter in and a teenage boy out. Then after a quiet lull, the rush is on; the mid-morning crowd, people popping out in their tea breaks to do a quick bit of shopping. He settles back, holding his empty takeaway coffee cup, which is more of a prop than anything, just to show some reason for him sitting there, and he starts counting. Twelve in through the door, a couple leave, six more in, two go out, three in, one out…
Deep down, he was having fun. The fact was, when all was said and done, for him, it simply comes down to statistical reciprocity.