Statistics Questions (255)

Suppose a population \(A\) has 100 observations 101, 102, ..., 200 and another population \(B\) has 100 observations 151, 152, ..., 250. If \(V_A\) and \(V_B\) represent the variances of the two populations, respectively, then \(V_A/V_B\) is equal to
The standard deviation of 25 numbers is 40. If each of the numbers is increased by 5, then the new standard deviation will be
If each observation of a raw data whose variance is \(\sigma\) is multiplied by \(h\), then the variance of the new set is
The SD of a variate \(x\) is \(\sigma\). The SD of the variate \(\dfrac{ax+b}{c}\), where \(a, b, c\) are constants, is
$x_1,x_2,\ldots,x_n$ are observations with mean $\bar{x}$ and variance $\sigma^2$. If $u_i=\dfrac{x_i-\bar{x}}{\sigma}$, then the standard deviation of $u_1,u_2,\ldots,u_n$ is