Method Score
1 24.4 23.2 25.0 19.7
22.2 24.4 23.8 18.0
2 22.1 19.5 17.3 19.7
22.3 23.2 21.4 22.6
3 23.3 22.8 22.4 23.7
20.4 23.5 20.8 24.113-4 RANDOMIZED COMPLETE BLOCK DESIGN 501(a) Does the type of alloy affect mean contact resistance? Use
0.01.
(b) Use Fisher’s LSD method to determine which means differ.
(c) Find a 99% confidence interval on the mean contact
resistance for alloy 3.
(d) Analyze the residuals for this experiment.
13-32. An article in Lubrication Engineering(December
1990) describes the results of an experiment designed to
investigate the effects of carbon material properties on
the progression of blisters on carbon face seals. The carbon
face seals are used extensively in equipment such as air
turbine starters. Five different carbon materials were tested,
and the surface roughness was measured. The data are as
follows:Carbon
Material
Type Surface Roughness
EC10 0.50 0.55 0.55 0.36
EC10A 0.31 0.07 0.25 0.18 0.56 0.20
EC4 0.20 0.28 0.12
EC1 0.10 0.16(a) Does carbon material type have an effect on mean surface
roughness? Use 0.05.
(b) Find the residuals for this experiment. Does a normal
probability plot of the residuals indicate any problem with
the normality assumption?
(c) Plot the residuals versus. Comment on the plot.
(d) Find a 95% confidence interval on the difference between
the mean surface roughness between the EC10 and the
EC1 carbon grades.
13-33. Apply the Fisher LSD method to the experiment in
Exercise 13-32. Summarize your conclusions regarding the
effect of material type on surface roughness.
13-34. An article in the Journal of Quality Technology
(Vol. 14, No. 2, 1982, pp. 80–89) describes an experiment inyˆijAlloy Contact Resistance
19597999899
99 99 94 95 98
2 104 102 102 105 99
102 111 103 100 103
3 119 130 132 136 141
172 145 150 144 135(a) Is there any difference in preparation methods? Use
0.05.
(b) Calculate the P-value for the F-statistic in part (a).
(c) Analyze the residuals from this experiment and comment
on model adequacy.
(d) Estimate the components of variance.
13-35. An article in the Journal of Agricultural
Engineering Research(Vol. 52, 1992, pp. 53–76) describes
an experiment to investigate the effect of drying temperature
of wheat grain on the baking quality of bread. Three temper-
ature levels were used, and the response variable measured
was the volume of the loaf of bread produced. The data are
as follows:Temperature (°C) Volume (CC)
70.0 1245 1235 1285 1245 1235
75.0 1235 1240 1200 1220 1210
80.0 1225 1200 1170 1155 1095(a) Does drying temperature affect mean bread volume? Use
0.01.
(b) Find the P-value for this test.
(c) Use the Fisher’s LSD method to determine which means
are different.
(d) Analyze the residuals from this experiment and comment
on model adequacy.
13-36. An article in Agricultural Engineering(December
1964, pp. 672–673) describes an experiment in which
the daily weight gain of swine is evaluated at different
levels of housing temperature. The mean weight of each
group of swine at the start of the experiment is considered to
be a nuisance factor. The data from this experiment are as
follows:for three different materials (all were silver-based alloys).
The data are as follows.which three different methods of preparing fish are evalu-
ated on the basis of sensory criteria and a quality score is
assigned. Assume that these methods have been randomly
selected from a large population of preparation methods.
The data are in the following table:c 13 .qxd 5/8/02 9:21 PM Page 501 RK UL 6 RK UL 6:Desktop Folder:TEMP WORK:PQ220 MONT 8/5/2002:Ch 13: