A bank manager wishes to estimate the average waiting time for customers in line for tellers. A random sample of 50 times is mea
sured and the average waiting time is 5.7 minutes. The population standard deviation of waiting time is 2 minutes. Which Excel function would be used to construct a confidence interval estimate?
In excel, the confidence.norm calculates the confidence value which then gives the confidence interval for a given population mean, probability of occurrence and sample number or size using Normal distribution statistics.
The mean is at the center of the confidence interval is given by the range
mean, μ ±CONFIDENCE.NORM. and it tells the degree of confidence that a value of the mean of a sample of data is about the mean of the population.
