Answer:
CI 95%(μ)= [13.506 ; 14.094]
Step-by-step explanation:
The confidence interval (CI) formula is:
CI (1-alpha) (μ)= mean+- [(Z(alpha/2))* σ/sqrt(n)]
alpha= is the proportion of the distribution tails that are outside the confidence interval. In this case, 5% because 100-90%
Z(5%/2)= is the critical value of the standardized normal distribution. In this case is 1.96
σ= standard deviation. In this case 0.75 day
mean= 13.8 days
n= number of observations
. In this case 25
Then, the confidence interval (90%) is:
CI 95%(μ)= 13.8+- [1.96*(0.75/sqrt(25)]
CI 95%(μ)= 13.8+- [1.96*(0.75/5)
]
CI 95%(μ)= 13.8+- (0.294)
CI 95%(μ)= [13.8-0.294 ; 13.8+0.294]
CI 95%(μ)= [13.506 ; 14.094]
