

1. 
A 1% level of confidence is given when ______. 


A. 
P = 95% 
B. 
none of these 


C. 
P = 99% 
D. 
P = 1% 


Hint 


2. 
From a population of 32 items, a sample of 25 items is chosen and found to have a standard deviation of 57.0. Find the standard error of the mean. 


A. 
10.1 
B. 
7.25 


C. 
11.4 
D. 
2.28 


Hint 


3. 
Use the partial table below. If = 6.4.0, N = 100, and = 37.1, find the interval about the sample mean that has a 1% level of confidence. 





A. 
about 35.4538.75 
B. 
about 36.0438.16 


C. 
about 35.1839.02 
D. 
about 35.8538.35 


Hint 


4. 
If , , and N = 150, find the interval such that the probability is 90% that the mean of the population lies within that interval. Use the table below to help you. 





A. 
48.628–55.103 
B. 
50.114–53.886 


C. 
49.760–54.240 
D. 
49.051–54.949 


Hint 


5. 
In a sample of 3,000 used cars, the average number of miles each car has been driven was 23,082 with a standard deviation of 4,608 miles. Find an interval of the number of miles about the sample mean that has a 1% level of confidence. Use the table below to help you. 





A. 
22,917–23,246 
B. 
23,003–23,160 


C. 
23,031–23,132 
D. 
22,865–23,299 


Hint 

