# Probability: Given the Mean and Standard deviation

## Homework Statement

The distribution of a drugs among addicts with autoimmune disorder is N(6.9, 16.81). What is the probability that one of these addicts enters your office and reports taking 16 drugs or more?

## The Attempt at a Solution

z = (16-6.9)/4.1 = 2.21
P(z >16) = 0.014 from the table
so P(z > 16) = 0.014 or 1.4%

Is this correct. It seems to simple and maybe I dont understand the concept

$$P[x\geq 16]=1-P[x < 16]$$
$$P[x\geq 16]=1-P[z < 2.21]= 1-0.986$$