;% Data from StatLib (ftp stat.cmu.edu/datasets)
;%
;% SUMMARY:
;%
;% Data from an experiment on the affects of machine adjustments on
;% the time to count bolts. Data appear as the STATS (Issue 10) Challenge.
;%
;% DATA:
;%
;% Submitted by W. Robert Stephenson, Iowa State University
;% email: wrstephe@iastate.edu
;%
;% A manufacturer of automotive accessories provides hardware, e.g. nuts,
;% bolts, washers and screws, to fasten the accessory to the car or truck.
;% Hardware is counted and packaged automatically. Specifically, bolts
;% are dumped into a large metal dish. A plate that forms the bottom of
;% the dish rotates counterclockwise. This rotation forces bolts to the
;% outside of the dish and up along a narrow ledge. Due to the vibration
;% of the dish caused by the spinning bottom plate, some bolts fall off
;% the ledge and back into the dish. The ledge spirals up to a point
;% where the bolts are allowed to drop into a pan on a conveyor belt.
;% As a bolt drops, it passes by an electronic eye that counts it. When
;% the electronic counter reaches the preset number of bolts, the
;% rotation is stopped and the conveyor belt is moved forward.
;%
;% There are several adjustments on the machine that affect its operation.
;% These include; a speed setting that controls the speed of rotation
;% (SPEED1) of the plate at the bottom of the dish, a total number of
;% bolts (TOTAL) to be counted, a second speed setting (SPEED2) that is
;% used to change the speed of rotation (usually slowing it down) for the
;% last few bolts, the number of bolts to be counted at this second speed
;% (NUMBER2), and the sensitivity of the electronic eye (SENS). The
;% sensitivity setting is to insure that the correct number of bolts are
;% counted. Too few bolts packaged causes customer complaints. Too many
;% bolts packaged increases costs. For each run conducted in this
;% experiment the correct number of bolts was counted. From an
;% engineering standpoint if the correct number of bolts is counted, the
;% sensitivity should not affect the time to count bolts. The measured
;% response is the time (TIME), in seconds, it takes to count the desired
;% number of bolts. In order to put times on a equal footing the
;% response to be analyzed is the time to count 20 bolts (T20BOLT).
;% Below are the data for 40 combinations of settings. RUN is the order
;% in which the data were collected.
;%
;% Analyze the data. What adjustments have the greatest effect on the
;% time to count 20 bolts? How would you adjust the machine to get
;% the shortest time to count 20 bolts? Are there any unusual features
;% to the data?
;%
;% The data description and data may be freely used for non-commercial
;% purposes and can be freely distributed. Copyright remains with the
;% author and STATS Magazine.
;%
(defun bolts ()
(data
:name 'bolts
:columns '($RUN SPEED1 TOTAL SPEED2 NUMBER2 SENS $TIME $T20BOLT)
:egs
'(
(25 2 10 1.5 0 6 5.70 11.40)
(24 2 10 1.5 0 10 17.56 35.12)
(30 2 10 1.5 2 6 11.28 22.56)
(2 2 10 1.5 2 10 8.39 16.78)
(40 2 10 2.5 0 6 16.67 33.34)
(37 2 10 2.5 0 10 12.04 24.08)
(16 2 10 2.5 2 6 9.22 18.44)
(22 2 10 2.5 2 10 3.94 7.88)
(33 2 30 1.5 0 6 27.02 18.01)
(17 2 30 1.5 0 10 19.46 12.97)
(28 2 30 1.5 2 6 18.54 12.36)
(27 2 30 1.5 2 10 25.70 17.13)
(14 2 30 2.5 0 6 19.02 12.68)
(13 2 30 2.5 0 10 22.39 14.93)
(4 2 30 2.5 2 6 23.85 15.90)
(21 2 30 2.5 2 10 30.12 20.08)
(23 6 10 1.5 0 6 13.42 26.84)
(35 6 10 1.5 0 10 34.26 68.52)
(19 6 10 1.5 2 6 39.74 79.48)
(34 6 10 1.5 2 10 10.60 21.20)
(31 6 10 2.5 0 6 28.89 57.78)
(9 6 10 2.5 0 10 35.61 71.22)
(38 6 10 2.5 2 6 17.20 34.40)
(15 6 10 2.5 2 10 6.00 12.00)
(39 6 30 1.5 0 6 129.45 86.30)
(8 6 30 1.5 0 0 107.38 71.59)
(26 6 30 1.5 2 6 111.66 74.44)
(11 6 30 1.5 2 0 109.10 72.73)
(6 6 30 2.5 0 6 100.43 66.95)
(20 6 30 2.5 0 0 109.28 72.85)
(10 6 30 2.5 2 6 106.46 70.97)
(32 6 30 2.5 2 0 134.01 89.34)
(1 4 20 2.0 1 8 10.78 10.78)
(3 4 20 2.0 1 8 9.39 9.39)
(5 4 20 2.0 1 8 9.84 9.84)
(7 4 20 2.0 1 8 13.94 13.94)
(12 4 20 2.0 1 8 12.33 12.33)
(18 4 20 2.0 1 8 7.32 7.32)
(29 4 20 2.0 1 8 7.91 7.91)
(36 4 20 2.0 1 8 15.58 15.58)
)))