Question

the mean of 17 observations is 30 observations 20 ,30,48 deleted and one observation 90 is inclined then find the means of the final observations

Answer 1

$\mathsf{Mean \: of \: 17 \: observations = \dfrac{sum \: of \: 17 \: observations}{17}} \\ \\ \\ \mathsf{30= \dfrac{sum \: of \: 17 \: observations}{17}} \\ \\ \\ \mathsf{30 \times 17 = sum \: of \: 17 \: observations} \\ \\ \\ \mathsf{510 = sum \: of \: 17 \: observations}$




Given that 20 , 30 , 48 are deleted and 90 is added . Now,

Total number of observations= ( 17 - 3 ) + 1 = 15



$\mathsf{New \: mean = \dfrac{ sum \: of \: 17 \: observations - 20 - 30 - 48 + 90 }{ 15}} \\ \\ \\ \mathsf{New \: mean = \dfrac{ 510- 20 - 30 - 48 + 90 }{ 15}} \\ \\ \\ \mathsf{ New \: mean = \dfrac{ 502}{ 15}}$


New Mean = 33.47