1.3 A certain polymer is used for evacuation systems
for aircraft. It is important that the polymer be resistant
to the aging process. Twenty specimens of the
polymer were used in an experiment. Ten were assigned
randomly to be exposed to an accelerated batch
aging process that involved exposure to high temperatures
for 10 days. Measurements of tensile strength of
the specimens were made, and the following data were
recorded on tensile strength in psi:
No aging: 227 222 218 217 225
218 216 229 228 221
Aging: 219 214 215 211 209
218 203 204 201 205
(a) Do a dot plot of the data.
(b) From your plot, does it appear as if the aging process
has had an effect on the tensile strength of this polymer? Explain.
(c) Calculate the sample mean tensile strength of the
two samples.
(d) Calculate the median for both. Discuss the similarity
or lack of similarity between the mean and
median of each group.
JAWABAN
1.3
(a) No aging: 227 222 218 217 225
218 216 229 228 221
Aging: 219 214 215 211
209218 203 204 201 205
(b) Yes, the aging process has reduced the tensile strength.
(c) ¯xAging = 209.90, ¯xNo aging = 222.10
(d) ˜xAging = 210.00, ˜xNo aging = 221.50. The means and medians are similar for each group.
