Question

If a random sample of 100 items is taken from a population in which the proportion of items having a desired attribute is p=0.30, what is the probability that the proportion of successes in the sample will be less than or equal to 0.34?

The probabilty will be ___.

Answer 1

For normal distribution of sampling proportion, P(p < A) = P(Z < (A - )/)

Sample size, n = 100

= p = 0.30

=

=

= 0.0458

P(the proportion of successes in the sample will be less than or equal to 0.34) = P(p 0.34)

= P(Z < (0.34 - 0.30)/0.0458)

= P(Z < 0.87)

= 0.8078