Question

Although studies continue to show smoking leads to significant health problems, 20% of adults in the United States smoke. Consider a group of 335 adults.

1. What is the probability that 80 or more smoke?

Answer 1

Solution :

Given that,

Using binomial distribution,

= n * p = 335 * 0.20 = 67

= n * p * q = 335 * 0.20 * 0.80 = 7.3212

Using continuity correction ,

P(x 79.5) = 1 - P(x   79.5)

= 1 - P[(x - ) / (79.5 - 67) / 7.3212]

= 1 -  P(z 1.71)  

= 0.0436

Probability = 0.0436