Question

Mean of 20 observationis 17. If in the observation , 40 is replaced. by 12 .find the new mean

Answer 1

Answer:

The new mean is 15.6

Step-by-step explanation:

Given :

Mean of 20 observations = 17

40 is replaced by = 12

To find :

The new mean

Solution :

• Mean = 17
• Number of observations = 20
• Sum of observations = x

$\bigstar \: {\boxed{\sf{Mean = \frac{Sum \: of \: Observations}{No. \: of \: Observations}}}}$

$\sf{\implies} \:17 = \dfrac{x}{20} \\ \\ \sf{\implies} \:x = 17 \times 20 \\ \\ \sf{\implies} \:x = 340$

Sum of Observations is 340.

As 40 is replaced by 12, new Sum of observations is = (340 - 40) + 12

$\rule{300}{1.5}$

$\textsf{\underline{\underline{New Mean =}}}$

• Sum of observations = (340 - 40) + 12
• Number of observations = 20
• Mean = ??

$\sf{\implies} \:Mean = \dfrac{(340 - 40) + 12}{20} \\ \\ \sf{\implies} \:Mean = \dfrac{300 + 12}{20} \\ \\ \sf{\implies} \:Mean = \dfrac{312}{20} \\ \\ \sf{\implies} \:Mean = 15.6$

$\therefore$ The new mean is 15.6

Answer 2

soln refers to the attachment