Question 3.

A manufacturer of outdoor copper mailboxes and lamps has received numerous complaints about premature corrosion. The manufacturer has identified the cause of the problem as the low-quality varnish used to coat the copper. You decide to replace your current varnish supplier with one of five possible alternatives. To determine which is best, use each of the five varnishes to coat 25 copper mailboxes and place the 125 mailboxes outside. Records, for each, the number of days until the first sign of corrosion is observed (Xr15-12)

a. State the null and alternate hypothesis for this scenario.

b. Is there enough evidence at the 5% significance level to allow the manufacturer to conclude that there are differences between the five varnishes?

b. What are the conditions required for the test performed in part b? Explain

c. Does it appear that the required conditions of the test in part b are met? Explain

Data for Q3.

Varnish 1	Varnish 2	Varnish 3	Varnish 4	Varnish 5
133	173	161	160	154
171	182	115	221	180
142	214	137	208	222
154	165	173	249	147
242	168	176	148	159
147	232	138	99	175
171	217	106	182	193
155	220	238	169	209
165	184	129	162	192
156	145	163	158	173
219	126	156	240	188
159	209	140	168	147
179	152	109	121	240
189	139	128	146	183
110	237	121	191	236
198	107	149	222	186
119	266	165	176	168
177	234	121	153	169
185	158	162	238	177
206	154	166	195	128
145	199	190	196	152
81	195	214	240	213
171	133	197	152	135
175	247	130	233	165
165	185	185	138	181