In: Statistics and Probability
13.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?
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 ] = 0.033
P(
>0.2 ) = 1 - P(
<0.2 )
= 1 - P((
-
) /
< (0.2-0.16) / 0.033)
= 1 - P(z <1.21 )
Using z table
= 1 -0.8869
proportion=0.1131