Answer: B. 1.414
Step-by-step explanation:
let x be the random variable denotes the number of die.
Numbers on 5-faced die = 1,2,3,4,5
Probability of getting any number = [tex]\dfrac{1}{5}[/tex]
Mean = [tex]\bar {x}=\sum p_ix_i[/tex]
[tex]\\\\\Rightarrow\bar{x}=\dfrac{1}{5}(1)+\dfrac{1}{5}(2)+\dfrac{1}{5}(3)+\dfrac{1}{5}(4)+\dfrac{1}{5}(5)\\\\=\dfrac{1}{5}(1+2+3+4+5)\\\\=\dfrac{1}{5}(15)=3[/tex]
Standard deviation: [tex]\sigma=\sum \sqrt{\dfrac{(x_i-\bar{x})^2}{N}}[/tex]
[tex]=\sqrt{\dfrac{(1-3)^2+(2-3)^2+(3-3)^2+(4-3)^2+(5-3)^2}{5}}\\\\=\sqrt{\dfrac{4+1+0+1+4}{5}}\\\\=\sqrt{\dfrac{10}{5}}\\\\=\sqrt{2}\approx1.414[/tex]
Hence, the standard deviation of the random variable x is 1.414.
Thus, the correct option is B.
