Question

the mean of 12 observations is 18 if one observation 30 is deleted find the new mean.​

Answer 1

mean = sum of observations / number of observations=

let the sum of observations be "a"

18 = a / 12

18 * 12 = a

216 = a

30 is deleted

216 - 30

186

mean = 186 / 17

= 10.9

therefore,

mean = 10.9