Probability is a branch of mathematics that deals with the occurrence of a random event.
Variance is  1.25 and standard deviation is  1.12 .
Since, Four balls numbered 1, 2, 3, and 4 are placed in a bowl
Here, X is random variable and it represents ball with number and P(X) represents probability.
X Â Â Â Â Â Â Â 1 Â Â Â Â 2 Â Â Â Â Â 3 Â Â Â Â Â 4
P(X) Â Â Â Â 1/4 Â Â Â 1/4 Â Â Â 1/4 Â Â Â Â 1/4
Mean (μ) = ΣXP(X)
       =  1/4  + 1/2 + 3/4 + 4/4
       = 5/2
Variance = Σ (X^2P(X))  - μ^2
Σ (X^2P(X))  = 1/4 + 4/4 + 9/4 + 16/4
       = 30/4 = 7.5
So, Variance = 7.5 - 6.25 = 1.25
[tex]Deviation = \sqrt{Variance}[/tex]
Standard deviation = Â [tex]\sqrt{1.25}[/tex] = 1.12
Learn more:
https://brainly.com/question/475676