Question 1040406
[{{{sqrt(((n-1)s^2)/X^2[alpha/2])}}},{{{sqrt(((n-1)s^2)/X^2[1-alpha/2])}}} ]

=[{{{sqrt((10*12^2)/X^2[0.025])}}},{{{sqrt((10*11^2)/X^2[0.975])}}} ]

=[{{{sqrt(1440/20.483)}}},{{{sqrt(1440/3.247)}}} ]

= [8.38, 21.06]

where {{{X^2[alpha/2] }}} is the chi-square distribution with df 11-1 = 10 and {{{alpha = 0.05}}}.