If the mean of the data : 7 , 8 , 9 , 7 , 8 , 7 , λ , 8 is 8 , then the variance of this data is
Question 18 Which of the following is not true? (A) (7+8)+9=7+(8+9) (B) (7×8)×9=7×(8×9) (C) 7+8×9=(7+8)×(7+9) (D) 7×(8+9)=(7×8)+(7×9)