Answer:
The best point of estimate for the true mean is:
Since the time can't be negative a good approximation for the confidence interval would be (0,5.248) minutes. The interval are tellling to us that at 95% of confidence the average late time is lower than 5.248 minutes.
Step-by-step explanation:
Information given
represent the sample mean for the late time for a flight
population mean
represent the population deviation
n=76 represent the sample size
Confidence interval
The best point of estimate for the true mean is:
The confidence interval for the true mean is given by:
(1)
The Confidence level given is 0.95 or 95%, th significance would be and
. If we look in the normal distribution a quantile that accumulates 0.025 of the area on each tail we got
Replacing we got:
Since the time can't be negative a good approximation for the confidence interval would be (0,5.248) minutes. The interval are tellling to us that at 95% of confidence the average late time is lower than 5.248 minutes.