Question

Many older homes have electrical systems that use fuses rather than circuit breakers. A manufacturer of 40-amp fuses wants to make sure that the mean amperage at which its fuses burn out is in fact 40. If the mean amperage is lower than 40, customers will complain because the fuses require replacement too often. If the mean amperage is higher than 40, the manufacturer might be liable for damage to an electrical system due to fuse malfunction. To verify the amperage of the fuses, a sample of fuses is to be selected and inspected. If a hypothesis test were to be performed on the resulting data, what null and alternative hypotheses would be of interest to the manufacturer?

Answer 1

Answer:

Alternative hypothesis 1:  the mean amperage at which the fuses burn out is > 40 amperes.

Alternative hypothesis 2:  the mean amperage at which the fuses burn out is < 40 amperes.

Step-by-step explanation:

Recall that the null hypothesis is the fact you want to refute and is in doubt.

So, in this specific case, the null hypothesis would be that the mean amperage at which the fuses burn out is 40 amperes.

The alternative hypothesis are those that want to refute the null hypothesis, in this case there are 2:

Alternative hypothesis 1:  the mean amperage at which the fuses burn out is > 40 amperes.

Alternative hypothesis 2:  the mean amperage at which the fuses burn out is < 40 amperes.