IDNLearn.com offers a unique blend of expert answers and community insights. Our platform is designed to provide quick and accurate answers to any questions you may have.

The breaking strength of hockey stick shafts made of two different graphite-kevlar composites yields the following results (in Newtons):
For Composite 1 the average and the standard deviation of the 14 hockey sticks are respectively 487.42 Newtons and 11.528 Newtons.
For Composite 2 the average and the standard deviation of the 12 hockey sticks are respectively 466.76 Newtons and 7.193 Newtons.
Use a 5% significance level to test the claim that the standard deviation of the breaking strength of hockey stick shafts made of graphite-kevlar composite 1 is different from the standard deviation of the breaking strength of hockey stick shafts made of graphite-kevlar composite 2.
Procedure:?


Sagot :

We don't have claim to strength of composite B is smaller than the strength of composite B by at least 2 [N].

From the given data we calculate μ₁s₁ and μ₂s₂ mean and standard deviation of samples A and B respectively.

μ₁ = 464.7, s₁ = 13.42 composite A

μ₂ = 479.49, s₂ = 13.38 composite B

n₁ : n₂ < 30 then we will use t-table.

Null hypothesis  H₀:μ₂-μ₁ ≥ 2

Alternative hypothesis Hₐ : μ₂ - μ₁ < 2

assuming CI 95%

α = 5% = 0.05

and degree of freedom is n₁ + n₂ - 2 = 9 + 9 - 2 = 16

then for the one tail t(c) = 1.746  

now we will compute t(s),

t(s) = (μ₂ - μ₁ - 2)/ sp×√1/n₁ + 1/n₂

sp²= (n₁ - 1) × s₁² + (n₂ - 1) × s₂² / n₁ + n₂ - 2

    = 8 × (13.42)² + 8 × (13.38)²/ 16

     = (8 × 180.1 + 8 × 179) / 16

sp² = 179.55

sp = 13.40

Therefore

t(s) = (479.49 - 464.7 - 2)/ 13.40 ×√1/9+1/9

     = 12.79 / 13.40 × 0.4714

     = 12.79 / 6.32

t(s) = 2.02

t(s) > t(c)

t(s) is rejection region.

Therefore we reject H₀

so we don't have evidence to claim to strength pf composite B is smaller than the strength of composite B at least 2 [N].

To know more about deviation here

https://brainly.com/question/17254047

#SPJ4