Question

The National Coffee Association reported that 64% of U.S. adults drink coffee daily. A random sample of 225 U.S. adults is selected. Round your answers to at least four decimal places as needed.

Find the probability that less than 59% of the sampled adults drink coffee daily.

Answer 1

Solution

Given that,

p = 64%=0.64

1 - p = 1-0.64=0.36

n = 225

= p =0.64

=  [p ( 1 - p ) / n] =   [(0.64*0.36) / 225 ] = 0.032

P( < 0.59) =

= P[( - ) / < (0.59-0.64) /0.032 ]

= P(z <-1.56 )

Using z table,   

probability =0.0594