Question

In a certain city it is known that 20% of the residents have a vehicle and the rest do not. If we take a sample of 256 people. What is the probability that the percentage of people who have vehicles is greater than 25%? (If the values of normal distribution table are being used show where they came from)

Answer 1

Solution

Given that,

p = 0.20

1 - p = 1-0.20=0.80

n = 256

= p =0.20

=  [p( 1 - p ) / n] = [(0.20*0.80) / 256] = 0.025

P( >0.25 )

= 1 - P(( - ) / < (0.25 -0.20) /0.025 )

= 1 - P(z < 2)

Using z table

= 1 -0.9772

probability=0.0228