"Durable press" cotton fabrics are treated to improve their recovery from wrinkles after washing. "Wrinkle recovery angle" measures how well a fabric recovers from wrinkles. Higher is better. Here are data on the wrinkle recovery angle (in degrees) for a random sample of fabric specimens. Assume the populations are approximately normally distributed with unequal variances. A manufacturer believes that the mean wrinkle recovery angle for Hylite is better. A random sample of 25 Hylite (group 1) and 20 Permafresh (group 2) were measured. Test the claim using a 10% level of significance.
Hylite |
Permafresh |
140 |
124 |
139 |
144 |
138 |
136 |
138 |
117 |
138 |
133 |
141 |
139 |
139 |
102 |
132 |
127 |
141 |
137 |
133 |
137 |
146 |
164 |
142 |
131 |
139 |
137 |
131 |
147 |
133 |
148 |
146 |
142 |
139 |
118 |
146 |
148 |
138 |
129 |
142 |
135 |
137 |
|
134 |
|
137 |
|
138 |
|
140 |
The Hypotheses for this problem are:
H0: μ1 = μ2
H1: μ1 > μ2
a) Find the p-value. Round answer to 4 decimal places.
Answer:
b) Choose the correct decision and summary.
Do not reject H0. There is evidence that the mean wrinkle recovery rate for Hylite is better than Permafresh. |
Do not reject H0. There is no evidence that the mean wrinkle recovery rate for Hylite is better than Permafresh. |
Reject H0. There is evidence that the mean wrinkle recovery rate for Hylite is better than Permafresh. |
Reject H0. There is no evidence that the mean wrinkle recovery rate for Hylite is better than Permafresh. |
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