Question 616184
  <pre><font face = "Tohoma" size = 3 color = "indigo"><b> 
Hi, 
A confidence interval estimate for the population mean is given to be (42.43, 51.02). 
(A) Determine the maximum error of the estimate, E. (51.02-42.43)/2 = 4.295
(B) Determine the confidence level used for the given confidence interval. 
standard deviation is 17.845 and the sample size is 47
 {{{4.295 = C*(17.854/sqrt(47))}}}
         C = 1.649  OR ~90% confidence level

	a	a/2	crtical regions	
80%	0.2	10%	z <-1.28155	z >+1.28155
90%	0.1	5%	z <-1.645	          z >+1.645
92%	0.8	4%	z <-1.751	          z >+1.751
95%	0.05	2.50%	z <-1.96	          z >+1.96
98%	0.02	1%	z <-2.326	          z >+2.326
99%	0.01	0.50%	z<-2.576	          z >+2.576