In the following probability distribution, the random variable $x$ represents the number of activities a parent of a 6 th- to 8 th-grade student is involved in. Complete parts (a) through (f) below.
\begin{tabular}{c|c|c|c|c|c}
$\mathbf{x}$ & 0 & 1 & 2 & 3 & 4 \\
\hline $\mathbf{P}(\mathbf{x})$ & 0.079 & 0.228 & 0.145 & 0.156 & 0.392
\end{tabular}
(d) Compute the standard deviation of the random variable $\mathrm{x}$.
The standard deviation is $\square$ activities.
(Round to one decimal place as needed.)

Step 1 ：Define the random variable $x$ as the number of activities a parent of a 6th- to 8th-grade student is involved in, with the following probability distribution: $x = [0, 1, 2, 3, 4]$ and $P(x) = [0.079, 0.228, 0.145, 0.156, 0.392]$.

Step 2 ：Calculate the mean (expected value) of the random variable $x$. The mean is calculated as the sum of the product of each value of the random variable and its corresponding probability. The mean is found to be approximately 2.554.

Step 3 ：Calculate the variance of the random variable $x$. The variance is the sum of the squared difference between each value of the random variable and the mean, multiplied by the corresponding probability. The variance is found to be approximately 1.961.

Step 4 ：Calculate the standard deviation of the random variable $x$. The standard deviation is the square root of the variance. The standard deviation is found to be approximately 1.4.

Step 5 ：\(\boxed{1.4}\) is the standard deviation of the random variable $x$, representing the number of activities a parent of a 6th- to 8th-grade student is involved in.