Given that is the mean and is the variance of n observations x1, x2, ...,xn.

Prove that the mean and variance of the observations ax1, ax2, ax3, ...., axn are and , respectively,

The given n observations in the question are x1, x2,…..xn

Also, mean =


And, variance = σ2


We know that,



According to the condition given in the question, if each of the observation is being multiplied by a and the new observation are yi the, we have:


yi = axi








Hence, mean of the observations ax1, ax2,…..axn is a


Now, by substituting the values of xi and in (i), we get:




Hence, the variance of the given observations ax1, ax2,….axn is a2σ2


4