Question 1040405
[{{{((n-1)s^2)/X^2[alpha/2]}}},{{{((n-1)s^2)/X^2[1-alpha/2]}}} ]

=[{{{(27*12.7^2)/X^2[0.05]}}},{{{(27*12.7^2)/X^2[0.95]}}} ]

=[{{{4354.83/40.113}}},{{{4354.83/16.151}}} ]

= [108.564, 269.632]

where {{{X^2[alpha/2] }}} is the chi-square distribution with df 28-1 = 27, and {{{alpha = 0.10}}}.