HLTH 501
CHAPTER P : C IROBLEMS ONFIDENCE NTERVALS
10 questions, 30 points
Chapter 06
Multiple Choice
1. Assume researchers are trying to find out the mean concentration levels of a specific drug in a
population of individuals’ blood during a clinical trail. The researchers find that the sample
population of 40 has a mean concentration of 7.1 mcg/mL with a standard deviation of 1.7
mcg/mL. Calculate a 95% confidence interval for the mean concentration level of the medication
for the population’s blood and interpret it.
a. The researchers are 95.0% confident the true mean concentration of medication in the
population’s blood is between 6.573 mcg/mL and 7.627 mcg/mL.
b. The researchers are 95.0% confident the true mean concentration of medication in the
population’s blood is between 6.235 mcg/mL and 7.165 mcg/mL.
c. The researchers are 95.0% confident the true mean concentration of medication in the
population’s blood is between 4.568 mcg/mL and 8.832 mcg/mL.
d. The researchers are 95.0% confident the true mean concentration of medication in the
population’s blood is between 4.5615 mcg/mL and 8.8385 mcg/mL.
2. Assume a researcher wants to compare the mean Alanine Aminotransferase (ALT) levels in
two populations, individuals who drink alcohol and individuals who do not drink alcohol. The
mean ALT levels for the individuals who do not drink alcohol is 35 with a standard deviation of
15, and 41 individuals were in the sample. The mean ALT levels for individuals who drink
alcohol is 73 with a standard deviation of 21, and 43 individuals were in the sample. Construct
and interpret a 95% confidence interval demonstrating the difference in means for those
individuals who drink alcohol when compared to those who do not drink alcohol.
a. The researchers are 95% confident that the true mean difference in ALT values between
the population of drinkers and population of non-drinkers is between 24.22 and 39.78.
b. The researchers are 95% confident that the true mean difference in ALT values between
