Monday, October 22, 2012

The Challenger O-ring data

The Challenger disaster data is one that I have seen numerous times.  The first time that I have seen this data (given below) was when I was a temporary laboratory instructor for an introductory statistics course. Typically, this data set is used to argue how important it is for someone to have basic data analysis skills. Another Challenger related data set can be found in the Journal of the American Statistical Association article that contains other variables and analysis.

The data set given below consists of observations made on various o-rings used in solid rocket boosters.  Each o-ring was tested at a different temperature and the erosion depth of the o-ring was measured.  The trend that one can see is that as temperatures decrease, the erosion depth of the o-rings increases, leading to a failure of the o-ring.  The general conclusion that was reached from this data set is that these o-rings should not have been used at cold temperatures.

Below is the data.  For more on the disaster, see wikipedia's page.

O-ring temp in °F Erosion depth,δ mils *
66.0 0.0
70.0 53.0
69.0 0.0
68.0 0.0
67.0 0.0
72.0 0.0
73.0 0.0
70.0 0.0
57.0 40.0
63.0 0.0
70.0 28.0
78.0 0.0
67.0 0.0
53.0 48.0
67.0 0.0
75.0 0.0
70.0 0.0
81.0 0.0
76.0 0.0
79.0 0.0
75.0 0.0
76.0 0.0

 

Monday, October 15, 2012

A New Section

Loyal Readers,

I have decided to add a new section to this blog.  Because I can't seem to get new datasets quick enough to discuss on this blog, I thought it might be fascinating to seek out some of the most historical datasets and discuss them on this blog.  For example, the O-ring data for the Challenger disaster.

I believe it is time that we (i.e., statisticians) began to collect all these well known and well studied datasets and put them in a single place.  This way, future statisticians can study their statistical roots through these data sets.

More to come and if you have any ideas for historical datasets, please leave me a comment.

Brian