A light bulb manufacturer guarantees that the mean life of a certain type of light bulb is at least 746 hours. A random sample of 21 light bulbs has a mean life of 729 hours. Assume the population is normally distributed and the population standard deviation is 62 hours. At alpha equals 0.05, do you have enough evidence to reject the manufacturer's claim? Complete parts (a) through (e). 1. Identify null hypothesis and alternative. 2. Identify critical values. 3. Identify standardized test statistic. 4. Decide whether to fail or reject the null hypothesis.
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Step 1
Identify null hypothesis and alternative hypothesis: The null hypothesis (H0) is that the mean life of the light bulbs is at least 746 hours, and the alternative hypothesis (H1) is that the mean life is less than 746 hours. H0: μ ≥ 746 H1: μ < 746 Show more…
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