Question

Suppose a large shipment of laser printers contained 9% defectives.

If a sample of size 209 is selected, what is the probability that the sample proportion will be greater than 10%? Round your answer to four decimal places.

Answer 1

Solution

Given that,

p = 0.09

1 - p = 1-0.09=0.91

n = 209

= p =0.09

=  [p( 1 - p ) / n] = [(0.09*0.91) / 209 ] = 0.0198

P( >0.10 ) = 1 - P( <0.10 )

= 1 - P(( - ) / < (0.10-0.09) / 0.0198)

= 1 - P(z <0.51 )

Using z table

= 1 -0.6950

=0.3050

probability=0.3050