Question

airthmathic mean of a group of 100 items is 50 and of anthor group Of 150 items is 100 . whtat will be the means of all items?​

Answer 1

Answer:

The mean and median of 100 items are 50 & 52

respectively. The value of the largest items

is 100. It was later found that it is 110.

The true mean and median are ________

Sol we know that Arithmetic mean =∑X/N

Given Mean =50

N=100

i.e, 50=

100

∑X

∑X=5000

Later found that it is 110

So the 100 items is wrong value

correct A.M = [∑X (wrong) + correct value of observation −

Incorrect value of observation]/N

correct Mean =[5000+110−100]/100

=[5110−100]/100

=

100

5010

=50.10

∴ The real or true mean value is 50.10

Median value is 52

Answer 2

Answer:

The mean of all items is 80.

Explanation:

Given:
For the first group,

Mean = 50

Number of items(N)= 100

For the second group,

Mean = 100

Number of items(N)= 150

We know that

$Mean=Sum/N$

1) 50 = Sum/100

∴Sum = 100*50=5000

2) 100 = Sum/150

∴Sum = 100*150=15000

Therefore, the mean of all the items = 15000+5000/100+150

                 =20000/250

                  =80

Thus, the mean of all items is 80.