MATH 110 (Introduction to Statistics) MODULE 6 PORTAGE LEARNING LATEST UPDATE||2024/2025.
, Exam Page 1
A new drug is introduced that is supposed to reduce fevers. Tests are done with the drug. The drug
is given to 60 people who have fevers. It is found that the mean time that it takes for the fever to get
back to normal for this test group is 350 minutes with a standard deviation of 90 minutes. Find the
80% confidence interval for the mean time that the drug will take to reduce all fevers for all people.
Case 1: large pop and large sample
xbar - z(s√n) < u < xbar + z(s√n)
n = 60
xbar = 350
s = 90
80% confidence interval (z) = 1.28
350 - 1.28(90√60) < u < 350 + 1.28(90√60) = 335.128, 364.872
335.13 < u < 364.87
Answer Key
A new drug is introduced that is supposed to reduce fevers. Tests are done with the drug. The drug
is given to 60 people who have fevers. It is found that the mean time that it takes for the fever to get
back to normal for this test group is 350 minutes with a standard deviation of 90 minutes. Find the
80% confidence interval for the mean time that the drug will take to reduce all fevers for all people.
The drug will ultimately sold to a very large number of people. So, we may assume a very large
population. Since the sample size is greater than 30, we should use Case 1: Very large population
and very large sample size.
We are given the sample mean and sample standard deviation. So, we have
n=60 x ¯= 350 s=90
We will use these values in the equation:
, Exam Page 1
A new drug is introduced that is supposed to reduce fevers. Tests are done with the drug. The drug
is given to 60 people who have fevers. It is found that the mean time that it takes for the fever to get
back to normal for this test group is 350 minutes with a standard deviation of 90 minutes. Find the
80% confidence interval for the mean time that the drug will take to reduce all fevers for all people.
Case 1: large pop and large sample
xbar - z(s√n) < u < xbar + z(s√n)
n = 60
xbar = 350
s = 90
80% confidence interval (z) = 1.28
350 - 1.28(90√60) < u < 350 + 1.28(90√60) = 335.128, 364.872
335.13 < u < 364.87
Answer Key
A new drug is introduced that is supposed to reduce fevers. Tests are done with the drug. The drug
is given to 60 people who have fevers. It is found that the mean time that it takes for the fever to get
back to normal for this test group is 350 minutes with a standard deviation of 90 minutes. Find the
80% confidence interval for the mean time that the drug will take to reduce all fevers for all people.
The drug will ultimately sold to a very large number of people. So, we may assume a very large
population. Since the sample size is greater than 30, we should use Case 1: Very large population
and very large sample size.
We are given the sample mean and sample standard deviation. So, we have
n=60 x ¯= 350 s=90
We will use these values in the equation:
