Portage Learning MATH 110 Module 8 Exam
Suppose we have independent random samples of size n1 = 420 and n2 = 510. The proportions of success in the
two samples are p1= .38 and p2 = .43. Find the 99% confidence interval for the difference in the two population
proportions.
Answer the following questions:
1. Multiple choice: Which equation would you use to solve this problem?
A.
B.
C.
D.
2. List the values you would insert into that equation.
3. State the final answer to the problem
From table 6.1, we see that 99% confidence corresponds to z=2.58. Notice that the sample sizes are each greater
than 30, so we may use eqn. 8.2:
Answer: B.
, So, the interval is (.-0.1333, -0.03326).
2. In certain hospital, nurses are required to constantly make rounds to check in on all of the patients. The
nursing supervisor would like to know if there is a difference between the number of rounds completed per shift
by the nurses on the day shift compared to the nurses on the night shift. So, the nursing supervisor checks the
records of 70 day shift nurses and finds that they complete an average (a mean) of 30 rounds per shift with a
standard deviation of 4.6 rounds per shift. The nursing supervisor also checks the records of 84 night shift
nurses and finds that they complete an average (a mean) of 25 rounds per shift with a standard deviation of 5.7
rounds per shift.
a) Find the 90% confidence interval for estimating the difference in the population means (µ1 - µ2).
b) Can you be 90% confident that there is a difference in the means of the two populations?
Answer the following questions:
1. Multiple choice: Which equation would you use to solve this problem?
A.
B.
C.
D.
2. List the values you would insert into that equation.
Suppose we have independent random samples of size n1 = 420 and n2 = 510. The proportions of success in the
two samples are p1= .38 and p2 = .43. Find the 99% confidence interval for the difference in the two population
proportions.
Answer the following questions:
1. Multiple choice: Which equation would you use to solve this problem?
A.
B.
C.
D.
2. List the values you would insert into that equation.
3. State the final answer to the problem
From table 6.1, we see that 99% confidence corresponds to z=2.58. Notice that the sample sizes are each greater
than 30, so we may use eqn. 8.2:
Answer: B.
, So, the interval is (.-0.1333, -0.03326).
2. In certain hospital, nurses are required to constantly make rounds to check in on all of the patients. The
nursing supervisor would like to know if there is a difference between the number of rounds completed per shift
by the nurses on the day shift compared to the nurses on the night shift. So, the nursing supervisor checks the
records of 70 day shift nurses and finds that they complete an average (a mean) of 30 rounds per shift with a
standard deviation of 4.6 rounds per shift. The nursing supervisor also checks the records of 84 night shift
nurses and finds that they complete an average (a mean) of 25 rounds per shift with a standard deviation of 5.7
rounds per shift.
a) Find the 90% confidence interval for estimating the difference in the population means (µ1 - µ2).
b) Can you be 90% confident that there is a difference in the means of the two populations?
Answer the following questions:
1. Multiple choice: Which equation would you use to solve this problem?
A.
B.
C.
D.
2. List the values you would insert into that equation.
