Filled my tank again today and the calculated figure was 53.9 mpg. This isn’t very great, but I am unconcerned as I know I am only seeing random variation. For this I use SPC and Western Electric Rules.
I spent a good number of years working in industries where data gathering was a necessity and statistical analysis was priority. When I worked in the semiconductor industry I was first introduced to Western Electric Rules and how they are implemented to control that manufactured parts are in specification. When I worked in Lexmark, manufacturing ink cartridges, statistical process control was most important, and the control of the process was in the hands of the workers on the shop floor. Data is only of any use when it is fresh, and has to be acted on immediately. There is no point in manufacturing a nightshift’s product only for the engineer to come in the next morning, measure it, and find it is all out of spec. As an example, Lexmark would weigh sample bottles every half hour. The information is entered into an SPC chart, and from that a decision is made whether any changes need to be made to the process.
We worked to what are known as Western Electric Rules, a system implemented by Western Electric back in 1956.
https://en.wikipedia.org/wiki/Western_Electric_rules It is these same rules I use to check on my fuel consumption figures, and decide if I am seeing a random spread or if I have an issue that needs looked at.
As an aside, the dashboard readout gave my mpg as 53.9. Remarkably close to the calculated figure.