Question

On the midnight shift, the number of patients with head trauma in an emergency room has the probability distribution shown below. x 0 1 2 3 4 5 Total P(x) .07 .36 .27 .17 .10 .03 1.00

Answer 1

1.96 ;

1.216

Explanation:

Given the data :

x : __0 _ 1 _ 2 _ 3 _4 _5 Total

P(x) .07 .36 .27 .17 .10 .03 1.00

. The mean, also called the expected value is defined as ;

E(X) = Σx*p(x)

E(X) = (0*0.07) + (1*0.36) + (2*0.27) + (3*0.17) + (4*0.10) + (5*0.03) = 1.96

The standard deviation, ; √var(x)

Var(X) = Σx²*p(x) - E(X)²

Var(X) = [(0² * 0.07) + (1² * 0.36) + (2² * 0.27) + (3² * 0.17) + (4² * 0.10) + (5² * 0.03)] - 1.96²

Var(X) = 5.32 - 3.8416

Var(X) =14784

SD(X) = √1. 4784 = 1.216