The following information is obtained regarding the height $(X)$ and weight $(Y)$ from a sample of ten students of a school.$\bar{x}=160, \bar{y}=55, \Sigma x y=90,000, S_x-25, S_y=10$. Find the correlation coefficient between the height and weight from it.
The wholesale price index numbers of the year $2017$ and $2018$ are found to be $150.2$ and $165.7$ respectively. Find the rate of inflation using index numbers of both the years.