A manufacturer of light bulbs claims that its light bulbs have a mean life of 1520 hr with a standard deviation of 85 hr. A random sample of 40 bulbs is selected for testing. If the sample produces a mean
value of 1498.3 hrs, is there sufficient evidence to claim that the mean life is less than the manufacturer
claimed? Use ߙ. = 01
1. Parameter?
2. Test?
3. Hypotheses?
4. Conditions?
5. Test Statistic?
6. P-value?
7. Critical Region?
8. Decision?
9. Conclusion?