Question

A manufacturing company is comparing the time needed to build a product using two different assembly methods, A and B. Sample data compiled from each method appears below. Using the 5% significance level, test the claim that the mean time needed for Method A is less than that of Method B (claim: μ_A < μ_B) by choosing the correct answer below.

• Test statistic: ‒2.64, Critical value(s): ‒1.645, Conclusion: The data support the claim that the mean time for Method A is less than Method B.

• Test statistic: 2.64, Critical value(s): 1.645, Conclusion: The data do not allow rejection of the claim that the mean time for Method A is less than Method B.

• Test statistic: 1.28, Critical value(s): ‒1.645, Conclusion: The data do not support the claim that the mean time for Method A is less than Method B.

• Test statistic: ‒2.64, Critical value(s): ±1.96, Conclusion: The data allows rejection of the claim that the mean time for Method A is less than Method B.

	Sample Size		Mean Time		Population Standard Deviation
Method A	32	units	6.54	minutes	0.9	minutes
Method B	38	units	7.17	minutes	1.1	minutes

Answer 1

The statistical software output for this problem is :

Critical value = -1.645

Test statistics = -2.64

Test statistic: ‒2.64, Critical value(s): ‒1.645, Conclusion: The data support the claim that the mean time for Method A is less than Method B.