Question

Use the following information to answer the next five exercises. Two metal alloys are being considered as material for ball bearings. The mean melting point of the two alloys is to be compared. 15 pieces of each metal are being tested. Both populations have normal distributions. The following table is the result. It is believed that Alloy Zeta has a different melting point.

Is this a right-, left-, or two-tailed test?

Short answer

Because the alternate hypothesis is testing for differences in melting points of two alloys with no mention of direction, this is a two-tailed test.

Step-by-step solution

Given Information

The table is

	Sample Mean Melting Temperatures$\left({}^{0}F\right)$	Population Standard Deviation
Alloy Gamma	800	95
Alloy Zeta	900	105

Is this a right-, left-, or two-tailed test

Because the alternate hypothesis is testing for differences in melting points of two alloys with no mention of direction, this is a two-tailed test.