Use the given margin of​ error, confidence​ level, and population standard​ deviation, sigma​, to find the minimum sample size required to estimate an unknown population​ mean, mu. Margin of​ error: 1.1 ​inches, confidence​ level: 90​%, sigmaequals2.9 inches A confidence level of 90​% requires a mimimum sample size of ______. ​(Round up to the nearest​ integer.)