Trackable Travel Rates-Part 5, A Single Trackable Series

[+shellbadger]

This post is an introduction to how to interpret the graphs and tables in the larger project to come. I will use my Love Bug series as the study collection.  All the Love Bugs are heart-shaped items attached to dog tags by rivets or chains, and are of different sizes and materials (leather, wood, stone, glass, metal, plastic). The series is not the largest, but is one of the oldest, the first ones were released in 2010, and examples have been released in every year since, now 2023. Refer to the figure and appended table below.

 

The bottom row in the table is the n, or the number of trackables in the series that achieved each successive drop. As noted in Part 3, the sample sizes decline from 274 trackables at Drop 1 to 11 at Drop 30. The decline results from attrition rates of 11-16% between the earliest drops to 4-9% between later drops…this was also demonstrated in Part 3.

 

The solid-colored lines in the graph represent the top three rows of the table. They are the maximum (blue line) and minimum (gray) number of days required for a single trackable to achieve a specified drop.  The orange line is the average days for all trackables to achieve a specific drop. The dotted line is the trend line for the average.

 

The jagged shape of the maximum line (blue) is caused by individual trackables having outliers whose cumulative days remain high until they disappear. An example is the trackable with the high of 3851 days at drop 11. Drop 12 was three days later, after which time it disappeared leaving the next highest maximum trackable to be tabulated and graphed.

 

The data can be read in several ways.  For example, the average for 274 trackables to make the first drop is 105 days after release. The maximum to the first drop was 1578 days (4.3 years), whereas the minimum days to the first drop was two days, a range of 1476 days (4.3 years). For 30 drops, the average is 2079 days (5.7 years), with maximum and minimum values at 3085 days (8.5 years) and 884 days (2.4 years). The average rate of travel for the Love Bug collection is 69 days per drop (2079 total days ÷ 30 drops)

 

Alternatively, if we want to know the average number of drops achieved in the first year (365 days), from the graph we can visually estimate between three and four drops per year.  Or, we can interpolate the value to 3.8 drops per year, (4 X 365) ÷ 382. The variables “days per drop” and/or “drops per year) will be the basis of comparisons among the various series of trackables.

 

Note that the line for the average (orange) days starts to become a little ragged in the range of 8-9 drops. This is the point where, because of decreasing sample sizes, a number of large outliers can unduly influence averages. One might normally believe that a sample size of more than 100 trackables would be adequate to mask those effects, but it is clearly not the case when intervals between drops are measured in multiple years. 

 

Part 6 of this post is a pool all series of trackable having representatives with 30 or more drops.

[Darwin473]

On 1/24/2023 at 10:39 PM, shellbadger said:

The average rate of travel for the Love Bug collection is 69 days per drop

 

Nice. And appropriate! 

[+shellbadger]

Sometimes one gets so immersed in a project, things are overlooked.