c) n = 1,150 and ; compute a 90% confidence interval.

90/2 = 45 => 4500

From Table A.5 we match 4500 to 1.64. z = 1.64.

 

 

 

 

 

 

 

 

 

The proportion population is estimated to be between 0.456 and 0.504.

 

d) n = 95 and ; compute a 88% confidence interval

88/2 = 44 è 4400

From Table A.5 we match 4400 to 1.55. z = 1.55.

 

 

 

 

 

 

 

 

 

 

The proportion population is estimated to be between 0.246 and 0.394.