Question

for 15 observation mean is 25 and if any one observation is taken 20 instead of 50.what is the value of the true mean

Answer 1

Answer:

27 is the mean when observation is 50.

____________________

Step-by-step explanation:

Given:

mean=25

total no. of observation = 15

To find:

right mean=?

$mean = \frac{sum \: of \: all \:observtions}{total \: no. \: observation}$

let sum of all observation be x when the mean is 25. therefore,

$25 = \frac{x}{15} \\ 25 \times 15 = x \\ x = > 375$

observation mistakenly taken= 20

right observation to be taken=50

therefore,

$mean = \frac{375 - 20 + 50}{15} \\ = > \frac{375 + 30}{15} \\ = > \frac{405}{15} \\ = > 27$

Hence,the right mean is 27.

_______________________________

hope it is clear to uh!!

_________________✌️✌️

Answer 2

Answer:

Step-by-step explanation:Okay so first we know we have 15 observations. Out of that one is 50 , let sum of rest 14 obs be 14x.
so first equation will be
(14x+50)/15=25
this gives x=325/14
now we are told to take 20 instead of 50 so second equation will be
(14x+20)/15
now we substitute value of x in here
this gives
(325+20)/15
that is
345/15=   23
Answer is 23.