The American Carbon Registry, www.americancarbonregistry.org, provides approved measurement methodologies for energy companies who wish to show greenhouse gas emission reduction through retrofitting high-bleed pneumatic controllers with low-bleed controllers. Summary sample data from the two manufacturers are shown in the table below. Are the variances of the two manufacturers equal?

Pneumatic Controller Methane Gas Emission (scfd)
Cemco	Invalco
? ? ? ? ??	? ? ? ? ? ?
s 1 = 147.2 ? ? ? ? ? ?	s 2 = 237.9 ? ? ? ? ? ??
n 1 = 18 ? ? ? ? ? ? ? ?	n 2 = 17 ? ? ? ? ? ? ? ??

(a)	Choose the appropriate hypotheses. Assume ? 1 2 is the variance of the manufacturer Cemco and ? 2 2 is the variance of the manufacturer Invalco.

a.

H ₀ : ? ₁ ² / ? ₂ ² = 1vs. H ₁ : ? ₁ ² / ? ₂ ² ? 1

b.

H ₀ : ? ₁ ² / ? ₂ ² ? 1vs. H ₁ : ? ₁ ² / ? ₂ ² = 1

	a
	b

(b)	Calculate the critical values for ? = 0.10. (Round your answers to 3 decimal places.)

??
? F R	??
? F L	? ?

(c)	Calculate the test statistic F calc . (Round your answer to 3 decimal places.)

? F calc

??

(d)	What is your conclusion?

??

? We (Click to select)cancannot conclude that the variances are not equal.