Answer:
95% Confidence interval: (96.06,103.94)
Step-by-step explanation:
We are given the following in the question:
Population mean, μ = 85
Sample mean, [tex]\bar{x}[/tex] = 100
Sample size, n = 30
Alpha, α = 0.05
Population standard deviation, σ = 11
95% Confidence interval:
[tex]\mu \pm z_{critical}\frac{\sigma}{\sqrt{n}}[/tex]
Putting the values, we get,
[tex]z_{critical}\text{ at}~\alpha_{0.05} = 1.96[/tex]
[tex]100 \pm 1.96(\frac{11}{\sqrt{30}} ) = 100 \pm 3.94= (96.06,103.94)[/tex]
(96.06,103.94) is the 95% confidence interval for the population mean test score.
