Answer:
We cannot conclude that the mean life of the bulbs is less than 950h.
Step-by-step explanation:
Be,
Sample mean (MX) = 930h
Population standard deviation (sigma) = 100h
Sample size (n) = 100
Significance level (alpha) = 0.01
Null hypothesis (H0): Mu = 950
Alternative hypothesis (Ha): Mu <950
Population mean in the null hypothesis (Mu0) = 950
Critical value (Z-alpha) = -2.32635.
The test statistic in this case is given by:
[tex]Z_{c} = \frac{(MX - Mu0)}{\sqrt{\frac{sigma^{2}}{n} } } = -2.000[/tex]
Since [tex]Z_{c}[/tex] is greater than Z-alpha, it is decided not to reject H0. That is, we cannot conclude that the average life of the bulbs is less than 950h.
