The mean of seven observations is 17. If the mean of the first four observations is 15 and that of t

Question

The mean of seven observations is 17. If the mean of the first four observations is 15 and that of the last four observations is 18 , then the fourth observation is:\

Professor PC Thomas Classes · Answer

(b): Let $x_{1}, x_{2}, x_{3}, x_{4}, x_{5}, x_{6}$ and $x_{7}$ be first seven observations.\Concept Applied - Mean for ungrouped data is $\bar{x}=\frac{x_{1}+x_{2}+\ldots x_{n}}{n}=\frac{\Sigma x_{i}}{n}$