Question 1049189
For a population with unknown mean  and known standard deviation , 
a confidence interval for the population mean is: CI = x̄ ± {{{z*sigma/sqrt(n)}}}
CI =  = 60 ± {{{z*10/sqrt(22)}}} 99% confidence level: z = 2.576
CI =  = 60 ± {{{2.576*10/sqrt(22)}}}
CI =  = 60 ± 5.5
Or
54.5 < {{{mu}}} < 65.5
b)
For a population with unknown mean  and unknown standard deviation , 
a confidence interval for the population mean is: CI = x&#772; ± {{{t*s/sqrt(n)}}}
CI = 60 ± {{{t*10/sqrt(22)}}} 
99% confidence level, Degree of Freedom(n-1) = 21: t = 2.831 (use Caculator 0r table)
CI = 60 ± {{{2.831*10/sqrt(22)}}} 
CI = 60 ± 6
0r
54 < {{{mu}}} < 66
per TY
 ME = 6.0 for b and it equals 5.5 for a. Rounded t0 nearest tenth.
Round as directed by Your Instructor