State the null and alternative hypotheses.

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.

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Alloy Gamma 800 Sample Mean Melting Temperatures (F) Population Standard Deviation 95 105 Alloy Zeta 900 Table 10.10