Question

60% of the studentsin a lecture are males. 100 students are selected randomly.

a.Find the standars error of the sample.

b.Find the probability of the sample proportion being greater than 0.70

Answer 1

Solution

Given that,

p = 0.60

1 - p = 1 - 0.60 = 0.40

n = 100

= p = 0.60

a) =  [p( 1 - p ) / n] = [(0.60 * 0.40) / 100] = 0.0490

b) P( > 0.70) = 1 - P( < 0.70)

= 1 - P(( - ) / < (0.70 - 0.60) / 0.0490)

= 1 - P(z < 2.04)

Using z table

= 1 - 0.9793

= 0.0207