Question

It has been estimated that 23% of all university students switch majors within their first two years of starting classes. If a random sample of 470 third-year students is taken at a city university, what is an estimate of the probability that 20% or less had switched majors within their first two years? Use Appendix B.1 for the z-values. (Round the z-value to 2 decimal places and the final answer to 4 decimal places.)

Probability           

Answer 1

Solution :

Given that ,

p = 0.23

1 - p = 0.77

n = 470

= p = 0.23  

= (p*(1-p))/n =  (0.23*0.77)/470 = 0.01941

P( 0.20 ) = P(( - ) / < (0.20 - 0.23) / 0.01941)

= P(z < -1.55)

= 0.0606

Probability = 0.0606