The Mining data set contains the results of an experiment to determine whether drilling time was faster for wet drilling or dry drilling
(Penner and Watts 1991). Tests were replicated three times for each method at different test holes. There is one observation per five-foot interval
for each replication.
The following list describes each variable.
depthdepth of the hole, in feet
driltimetime to drill the last five feet of the current depth, in minutes
methoddrilling method, wet or dry
repreplicate number