Answer:
b) yes
The manufacturer has the right to state that the light bulbs last on average 400 hours
Step-by-step explanation:
Explanation:-
Given sample size 'n' = 64
Given standard deviation of the Population (σ)=100
Mean of the sample (x⁻) = 350 hours
95% of confidence interval is determined by
[tex](x^{-} -Z_{0.95} \frac{S.D}{\sqrt{n} } , x^{-} +Z_{0.95} \frac{S.D}{\sqrt{n} } )[/tex]
([tex](350 -1.96 \frac{100}{\sqrt{64} } , 350+1.96\frac{100}{\sqrt{64} } )[/tex]
(350-24.5 , 350+24.5)
(325.5 , 374.5)
Conclusion:-
Yes
The manufacturer has the right to state that the light bulbs last on average 400 hours
