Question

Mean of right observation is 25. If one observation 11 is excluded, find the mean of the remaining?

Answer 1

let the eight observations be

$x_{1} \: \: x_{2} \: \: x_{3} \: \: x_{4} \: \: x_{5} \: \: x_{6} \: \: x_{7} \: \: x _{8} \\(x_{1} + x_{2} + \: x_{3} \: + \: x_{4} \: + \: x_{5} \: + \: x_{6} \: + \: x_{7} \: + \: x _{8}) \: \div 8 = 25 \\ \\ x_{1} + x_{2} + \: x_{3} \: + \: x_{4} \: + \: x_{5} \: + \: x_{6} \: + \: x_{7} \: + \: x _{8} \: = 200 \\ (x_{1} + x_{2} + \: x_{3} \: + \: x_{4} \: + \: x_{5} \: + \: x_{6} \: + \: x_{7}) \: \div 7 \: =( 200 - 11) \div 7 \\ = 189 \div 7 = 27$

The Answer: 27