1. Construct an 80​% confidence interval to estimate thepopulation mean when x overbarx=128 and s​ =27 for the sample sizesbelow.​
a)n=20       
​b)n=50       
​c)n=90
​a) The 80​% confidence interval for the population mean whenn=20 is from a lower limit of ____ to an upper limit of _____.(Round to two decimal places as​ needed.)
_______________________________________________________________________
2. Determine the margin of error for a confidence interval toestimate the population mean with n=25 and s-12.5 for the followingconfidence levels:
a. 80% b. 90% c.99%
