NDA Mathematics Question (2025) — Solution

Step-by-step solution

Let the unit of observation x_i be u. The mean is given by x = 1 n x_i, which has the unit u. The variance is given by ^2 = 1 n (x_i - x )^2, which has the unit u^2. Thus, mean and variance have different units of measurement. Statement I is incorrect. The mean deviation is given by 1 n |x_i - x |, which has the unit u. The standard deviation is given by = 1 n (x_i - x )^2 , which has the unit u^2 = u. Thus, mean deviation and standard deviation have the same unit of measurement. Statement II is correct. Answer: II only