Question

In: Statistics and Probability

The breaking strength of hockey stick shafts made of two different graphite-kevlar composites yields the following...

The breaking strength of hockey stick shafts made of two different graphite-kevlar composites yields the following results (in Newtons):

Composite 1:

479 505.3 471.1 488.6 467.2
483.4 491.1 481.2 480.7 484.5
470.9 480 472.6 485.4 469.1
482.2 478.2 490.7 468.1

(Note: The average and the standard deviation of the data are respectively 480.5 Newtons and 9.6 Newtons.)

Composite 2:

506 521 474.4 496.6 517.5
506.3 511.3 486.9 499.3 466.4
507.3 527

(Note: The average and the standard deviation of the data are respectively 501.7 Newtons and 18.26 Newtons.)

Use a 10% 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 less than the standard deviation of the breaking strength of hockey stick shafts made of graphite-kevlar composite 2.

Procedure: Select an answer

Two proportions Z Hypothesis Test

Two means T (non-pooled) Hypothesis Test

Two paired means Z Hypothesis Test

Two means Z Hypothesis Test

Two variances F Hypothesis Test

Two means T (pooled) Hypothesis Test

Assumptions: (select everything that applies)

  • Sample sizes are both greater than 30
  • The number of positive and negative responses are both greater than 10 for both samples
  • Population standard deviation are unknown but assumed equal
  • Population standard deviation are unknown
  • Simple random samples
  • Population standard deviations are known
  • Independent samples
  • Paired samples
  • Normal populations

Step 1. Hypotheses Set-Up:

H0:H0: Select an answer μ

μ₁-μ₂

p₁-p₂

σ₁²/σ₂²  

=

where Select an answer

p's are

μ's are

μ=μ₁-μ₂ is

σ's are

Select an answer

population means

difference between population means

population proportions

population standard deviations  and the units are

Select an answer

Watt

J

N

lbs

Ha:Ha: Select an answer μ₁-μ₂

μ

p₁-p₂

σ₁²/σ₂²

and

>

<  

and the test is Select an answer

Left-Tail

Two-Tail

Right-Tail

Step 2. The significance level α=_____ %

Step 3. Compute the value of the test statistic: Select an answer (z₀ t₀ χ²₀ f₀) = ______(Round the answer to 3 decimal places)

Step 4. Testing Procedure: (Round the answers to 3 decimal places)

CVA PVA
Provide the critical value(s) for the Rejection Region: Compute the P-value of the test statistic:
left CV is____and right CV is ____ P-value is ____

Step 5. Decision:

CVA PVA
Is the test statistic in the rejection region? Is the P-value less than the significance level?
no or yes no or yes

Conclusion: Select an answer (Do not reject the null hypothesis in favor of the alternative. or Reject the null hypothesis in favor of the alternative.)

Step 6. Interpretation:

At 10% significance level we Select an answer (DO NOT or DO) have sufficient evidence to reject the null hypothesis in favor of the alternative hypothesis.

Solutions

Expert Solution

1.procedure:2 variances F hypothesis test.

2.Assumptions: 1.normal population

2.population standard deviation are unknown but assumed equal.

3.simple random samples.

4.independent samples.

3.Ho: . Units are :N(newton since breaking strength is a kind of force)

4.H1:. Left-tailed test.

5.significance level:=10%=0.10

6.value of test statistic:

The provided sample variances are

s12=333.42 and s22=92.16 and the sample sizes are given by n1​=12 and n2​=19

The F-statistic is computed as follows:

7.rejection region:

Based on the information provided, the significance level is α=0.10, and the the rejection region for this left-tailed test is

R={F:F<FL​=1.912}.

8.p-value=0.993872

9.test-statistic=3.617>1.912 hence test statistic dienst lie in the reject kon region.

10.p-value=0.993872>0.10 no it is not less than the significance level.

11.do not reject the null hypothesis in favour of the alternative.

12At 10% significance level we do not have sufficient evidence to reject the null hypothesis in favour of the alternative hypothesis.

Please rate my answer and comment for doubts.


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