Question

A jar manufacturer is very concerned about the consistency of the diameters of jars produced by his machines and believes that the jars produced by machine "A" have a different variance in diameter than the variance in diameter from machine "B". A sample of 18 jars from machine "A" has the sample variance of 0.0494. A sample of 2 jars from machine "B" has the sample variance of 0.0424. Construct the 95% confidence interval for the ratio of the population variances. Round your answers to four decimal places. Lower & Upper Endpoints?

Answer 1

Solution :

Solution :

The statistic software output for this problem is:

Two sample variance summary confidence interval:
σ₁² : Variance of population 1
σ₂² : Variance of population 2
σ₁²/σ₂² : Ratio of two variances

95% confidence interval results:

Ratio	Num. DF	Den. DF	Sample Ratio	L. Limit	U. Limit
σ12/σ22	17	1	1.1650943	0.001178371	7.0395155

Lower Endpoint = 0.0012 (4 decimal)

Upper Endpoint = 7.0395