Answer:
The standard deviation of this probability distribution is 1.2.
Step-by-step explanation:
We have that:
P(X = 0) = 0.25
P(X = 1) = 0.3
P(X = 2) = 0.1
P(X = 3) = 0.35
Mean:
Each value multiplied by its probability. So
Variance:
Sum of the squares of the values subtracted from the mean, and multiplied by its probability.

Standard deviation:
Square root of the variance. So

The standard deviation of this probability distribution is 1.2.
Answer:
35.5 cm
Step-by-step explanation:
The perimeter (P) is calculated as
P = (2 × 6.75 ) + (2 ×
)
= 13.5 + (2 × 11) = 13.5 + 22 = 35.5 cm