Question

If the mean of 10 observations is 20 and th:
of 10 observations is 20 and that of another 15 observations, is 16. find the mean of all the 25
observation ​

Answer 1

Answer:

Step-by-step explanation:

We know mean =

observation

sum

​

For first 10 observations:

20=

10

sum1

​

sum1=sum of first 10 observations

sum1=20×10=200

For another 15 observations:

16=

15

sum2

​

sum2= sum of another 15 observations

sum2=16×15=240

Mean of all 25 observations:

mean=

25

sum1+sum2

​

mean=

25

200+240

​

=

25

440

​

=17.6

Answer 2

Answer:

Step-by-step explanation:

We know mean =

observation

sum

​

For first 10 observations:

20=

10

sum1

​

sum1=sum of first 10 observations

sum1=20×10=200

For another 15 observations:

16=

15

sum2

​

sum2= sum of another 15 observations

sum2=16×15=240

Mean of all 25 observations:

mean=

25

sum1+sum2

​

mean=

25

200+240

​

=

25

440

​

=17.6