A disease is inherited by a child with a probability of $1/4$. In a family with two children, the probability that exactly one sibling is affected by this disease is

Consider the data set $14, 18, 14, 14, 10, 29, 33, 31, 25$. If you add $20$ to each of the values, then both mean and variance change both mean and variance are unchanged the mean is unchanged, variance changes the mean changes, the variance is unchanged

A normal random variable has mean equal to $0$, and standard deviation equal to $3$. The probability that on a random draw the value of this random variable is greater than $0$ is __________ (round off to $2$ decimal places).

The probability distribution for a discrete random variable $X$ is given below. $\begin{array}{|c|c|c|c|c|} \hline X & 1 & 2 & 3 & 4 \\ \hline P(X) & 0.3 & 0.4 & 0.2 & 0.1 \\ \hline \end{array}$The expectation value of $X$ is (up to one decimal place) _____________