Hello. In this post, I will talk about an example on how statistics is used out there in the real world based on a experience I had while riding inside a city bus a few days ago.
I was getting back home by bus after a few job interviews. Inside the long stretch city transit bus, I took my seat in the very back. There was an old lady with clipboards and paper who was asking as many riders as she could if there would like to volunteer about five minutes of their time for a survey. As someone who knows some statistics, I thought this data collection method was genius. I took the time to do the survey as the bus ride from point A to point B was an expected thirty minutes which was way more than five minutes.
The survey questions included questions based on age, income levels, frequency usages, rating type questions (Rate from 1 to 7 for example), and some short answer questions where you could give recommendations to improve service.
I think such a survey like this was possible as the bus was not really busy (outside rush/peak hours). It also made sense to ask bus riders in person when they are already there versus trying to convince riders to complete surveys on the internet or by mail. This is a way of reducing costs and is a more targeted and time-efficient way to gather data.
I doubt that this survey selection method will work with all buses or during rush hours where the buses are busy. Therefore, there exists a selection bias that is unavoidable. It is costly to try to survey every possible transit rider inside every bus. Refer to my previous article on how statistics is based on partial information here for more detail.
Not everyone will have much time to complete a five minute survey if their bus ride is expected to be less a five minute ride. This contributes to the selection bias slightly.
I am not sure about everyone who conducted the survey but I thought that the existence of a survey inside a bus conveys that the bus system is proactive in trying to understand their customers. The data would be analyzed in order to help decision makers make system improvements in an effort for members of the public to consider public transit as a viable alternative to car driving.
If you are taking public transit and there is someone conducting surveys inside a city bus or subway train, you should not freak out. It is very likely that it would be survey trying to gather data.
The bus image is taken from http://www.king-long.com/3-1-3-18m-city-bus.html.