8.25

Use the information about each of the following samples to compute the confidence interval to estimate p.

a)      n = 44 and; compute a 99% confidence interval.

b)      n = 300 and; compute a 95% confidence interval.

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

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

 

 

 

 

 

a) n = 44 and; compute a 99% confidence interval

 

99/2 = 49.5

From Table A.5, 4950 is between 2.57 and 2.58. Choosing 2.57 for z.

 

 

 

 

 

 

 

 

 

 

 

 

The proportion population is estimated to be between 0.316 and 0.704.

 

b) n = 300 and; compute a 95% confidence interval.

95/2 = 47.5

From Table A.5 we match 4750, therefore z = 1.96.

 

 

 

 

 

 

 

 

 

The proportion population is estimated to be between 0.777 and 0.863.