Question

"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
141	124
140	145
138	136
138	117
138	133
141	139
141	105
132	127
141	137
135	139
146	165
142	131
139	137
131	147
133	148
146	142
139	116
146	148
137	133
142	136
137
134
137
138
143

The Hypotheses for this problem are:

H₀: μ₁ = μ₂

H₁: μ₁ > μ₂

Find the p-value. Round answer to 4 decimal places.  Make sure you put the 0 in front of the decimal.

p-value =

Answer 1

Given:

Assume the populations are approximately normally distributed with unequal variances.

A manufacturer believes that the mean wrinkle recovery angle for group 1 is better.

A random sample of 25 (group 1) and 20 (group 2) were measured.

	Group 1	Group 2
Sample size, n	25	20
Sample mean,	139	135.25
Standard deviation, s	4.10	13.31

Therefore P-value is 0.1186.