Question

If the mean of 10 observations is 3, and mean of 15 observations is 8. Find the mean of all observations ?

Answer 1

Answer:

6

Step-by-step explanation

===> Mean of 10 observations is 3.

∴ Sum1 = 10 x 3 = 30

===> Mean of 15 observations is 8.

∴ Sum2 = 15 x 8 = 120

Total = sum1  + sum2 = 30 + 120 = 150

Total observations= 10 + 15 = 25

Mean = total / no. of ob. = $\frac{150}{10+15} = \frac{150}{25} = 6$