A company manufactures electric light bulbs whose lifetime is normally distributed with a mean of 800 hours and a standa
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A company manufactures electric light bulbs whose lifetime is normally distributed with a mean of 800 hours and a standa
company manufactures electric light bulbs whose lifetime is normally distributed with a mean of 800 hours and a standard deviation of 40 hours. If a random sample of 30 light bulbs yields an average life time of only 788 hours. Test the hypothesis that µ-800 hours versus the alternative µ* 800 hours. By using a significance level of 4%, it can be concluded that A. Z= -2.64 and reject HO B. Z= -2.64 and accept HO C. Z= -1.64 and accept HO D. = -1.64 and reject HO
A