A light bulb manufacturer would like to supply only those bulbs which have a life of 2,000 hours or more. Otherwise, it wants the bulbs to be rejected at the assembly line. The statistician hired by the bulb manufacturer is trying to frame the situation as a hypothesis testing problem. He should specify the null and alternate hypothesis as:
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A. B. C. D.D
In any experiment, you have a natural candidate for a default hypothesis that is maintained to be true until there is sufficient evidence to reject it. This is the hypothesis that must be selected as the null. Inthe present example, the manufacturer is in the business of supplying bulbs which have an average life of more than 2000 hours. So it is logical to assume that the processes usually produce such bulbs and occasionally produce faulty bulbs which have a shorter average life.
Hence, the null hypothesis must be that any given bulb has an average life of more than 2000 hours and the alternative hypothesis must be the complement (i.e. average life is less than 2000 hours).