Question

27. A clothing manufacturer wanted to compare the mean thermal insulation of cotton fabrics and triacetate fabrics. A sample of 36 cotton fabrics gave X1 = 12.3 and $i = 3. A sample of 48 triacetate fabrics gave X2 = 8.6 and $2 = 2 What is the 93% confidence interval for the difference between the mean insulation of cotton and triacetate fabrics? I (a) (2.938, 4.462) (b) (2.416, 4.984) (c) (2.152, 5.248) (d) (3.188, 4.212) (e) (2.654, 4.746)

Answer 1

Given Date n = 36 n = 12.3 Si-3 D2 = 48 = 8.6 S2-2 93/.CI 70-93 x=1-0.93 = 0.02 Jx12 = Zootl2 = 20.036 = 1.812 From Excel NORISINVO-C 357 93%.cz = (1 - F) I 22/2 X (s? it ni S2 nz V (12.3-8.6) + 1.812* 32 36 2² V 48 - 3.7 +1.646 937.cĮ = 2.654 ; 4.746 e is cerrect Option