The mean life expectancy of new light bulbs produced by an A

The mean life expectancy of new light bulbs produced by an American company has been 4000 hours. Management believes that due to a new production process, the life expectancy of their light bulbs has increased. In order to test the validity of their belief, the correct set of hypotheses is

As the claim is the the life expectancy increased, then we use a > sign in the alternative hypothesis.

Thus,