An auto manufacturer wants to estimate the annual income of

An auto manufacturer wants to estimate the annual income of owners of a particular model of automobile. A random sample of 200 current owners is taken. The population standard deviation is known. Which Excel function would not be appropriate to use to construct a confidence interval estimate?

Solution

we use z instead of t because population standard deviation is known. NORMSINV() will be used to find critical values of z. You could also use NORMINV(,0,1), where 0 and 1 represent the fact it is standard normal. Microsoft also updated the function\'s name to make it more accurate, new functions are NORM.S.INV() and NORM.INV()