A small diner gets its eggs from two different suppliers. Uniformity of the weight of the eggs is an important quality parameter on which the suppliers are judged. A sample of 35 eggs from supplier A had a standard deviation in weight of 1.2 gm, while a sample of 45 eggs from supplier B had a standard deviation of 0.85 gm in weight. Construct a 98% confidence interval for the standard deviation of the weight of eggs provided by supplier A. At a 2% significance, conduct the appropriate hypothesis test to determine if there is any difference in the standard deviation of weight of eggs provided by the two suppliers.
A small diner gets its eggs from two different suppliers. Uniformity of the weight of the eggs is an important quality parameter on which the suppliers are judged. A sample of 35 eggs from supplier A had a standard deviation in weight of 1.2 gm, while a sample of 45 eggs from supplier B had a standard deviation of 0.85 gm in weight.
- Construct a 98% confidence interval for the standard deviation of the weight of eggs provided by supplier A.
- At a 2% significance, conduct the appropriate hypothesis test to determine if there is any difference in the standard deviation of weight of eggs provided by the two suppliers.
1.
The degrees of freedom is,
Critical value for :
The right-tail area is,
The critical value of at 34 degrees of freedom can be obtained using the excel formula “=CHISQ.INV.RT(0.01,34)”.
The critical value is 56.0609.
Critical value for :
The right-tail area is,
The critical value of at 34 degrees of freedom can be obtained using the excel formula “=CHISQ.INV.RT(0.99,34)”.
The critical value is 17.7892.
The 98% confidence interval for the standard deviation of the weight of eggs provided by supplier A is,
Thus, the 98% confidence interval for the standard deviation of the weight of eggs provided by supplier A is .
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