Question

The coefficient of variation of the rainfall for six rain gauge stations in catchments was found to be 29.54%. The optimum number of stations in the catchments for an admissible 10% error in the estimation of the mean rainfall will be

• A. 3
• B. 6
• C. 9
• D. 12

Answer 1

The correct option is C 9

The number of optimum stations can be given as
$N={\left(\frac{C_v}{\epsilon }\right)}^2={\left(\frac{29.54}{10}\right)}^2$
$=8.72\approx 9\text{stations}$