Question

the mean of 17 observations is 20.if the mean of first 9 observations is 23 and of that of last 9 observations is 18 ,the 9th observation is​

Answer 1

Answer:

9th observation = Sum of first 9 observations + sum of last 9 observations-sum of 17 observations

Let 9th observation be 'x'.

Sum of first 9 observations = 9x23 = 207

Sum of last 9 observations = 9x18 = 162

Sum of 17 observations = 340

Hence, x= 207+162 - 340

x=29