Q9 An experiment was carried out to compare the wear resista

An experiment was carried out to compare the wear resistance of two different materials for making the soles of children

95% confidence interval for the difference between the mean wear amounts for the two materials is given by

= ( Dbar - t_n-1 * sqrt(s²_D/n) , Dbar- t_n-1 * sqrt(s²_D/n))

= (0.212 - 2.16* (0.131/sqrt(14) ), 0.212 + 2.16* (0.131/sqrt(14) )

= (0.212 - 0.0756, 0.212 + 0.0756) = (0.13638, 0.2876) = (0.136, 0.288) Ans is C