Confidence Interval

							CONFIDENCE INTERVALS

A Pima County administrator, who earns $83,500 a year, believes that he deserves
to make more. So he investigates other counties comparable to Pima and finds
the saleries of 50 administrators whose job is comparable to his.

From this sample of 50, he computes the mean to be $88,989.
Since his salary is less than this, he argues that he deserves a raise.
But his boss claims that he could find another sample of 50 with a mean lower than the administrato

Therefore, the administrator decided to calculate the 95% confidence level.
The 95% confidence level means that the probability of the true mean lying within this interval is 95

Now the administrator calculates the following:
StDev = $22,358
    n =    50
   zo =   1.96
er than the administrators salary.


within this interval is 95%.