Question

If a random sample of 125 items is taken from a population in which the proportion of items having a desired attribute is p = 0.16, what is the probability that the proportion of successes in the sample will be more than 0.2?

Answer 1

Solution

Given that,

p = 0.16

1 - p = 1-0.16=0.84

n = 125

= p =0.16

=  [p( 1 - p ) / n] = [(0.16*0.84) / 125 ] = 0.0328

P( > 0.2) = 1 - P( <0.2)

= 1 - P(( - ) / < (0.2-0.16) / 0.0328)

= 1 - P(z <1.22 )

Using z table

= 1 -0.8888

=0.1112

probability=0.1112