A researcher wishes to determine whether people with high blood pressure can reduce their blood pressure by following a particular diet.Subjects were randomly assigned to a treatment group and a control group.The mean blood pressure was determined for each group,and a 90% confidence interval for the difference in the mean between the treatment group and the control group,
-
,was found to be (-26,-6).
A)We are 90% confident that a randomly selected subject in the treatment group had a blood pressure between 6 and 26 points lower than a randomly selected subject in the control group.
B)We are confident that 90% of all people who follow the particular diet will have a blood pressure between 6 and 26 points lower than people who do not follow the diet.
C)We know with 90% confidence that people who follow the diet have an average blood pressure between 6 and 26 points lower than people who do not follow the diet.
D)We know with 90% confidence that people who follow the diet have an average blood pressure between 6 and 26 points higher than people who do not follow the diet.
E)We know that 90% of all experiments done on the population will show that the average blood pressure for people who follow the diet is between 6 and 26 points lower than the average blood pressure for people who do not follow the diet.

Question

A researcher wishes to determine whether people with high blood pressure can reduce their blood pressure by following a particular diet.Subjects were randomly assigned to a treatment group and a control group.The mean blood pressure was determined for each group,and a 90% confidence interval for the difference in the mean between the treatment group and the control group, 
- 
,was found to be (-26,-6).
A)We are 90% confident that a randomly selected subject in the treatment group had a blood pressure between 6 and 26 points lower than a randomly selected subject in the control group. 
B)We are confident that 90% of all people who follow the particular diet will have a blood pressure between 6 and 26 points lower than people who do not follow the diet. 
C)We know with 90% confidence that people who follow the diet have an average blood pressure between 6 and 26 points lower than people who do not follow the diet. 
D)We know with 90% confidence that people who follow the diet have an average blood pressure between 6 and 26 points higher than people who do not follow the diet. 
E)We know that 90% of all experiments done on the population will show that the average blood pressure for people who follow the diet is between 6 and 26 points lower than the average blood pressure for people who do not follow the diet.

Quizplus · Accepted Answer

The 90% confidence interval (-26, -6) indicates that we can be 90% confident that the true difference in mean blood pressure between the treatment and control groups is between -26 and -6. Since the interval is entirely negative, this means the treatment group had a lower mean blood pressure than the control group. Therefore, we can say with 90% confidence that people who follow the particular diet have an average blood pressure between 6 and 26 points lower than people who do not follow the diet. Options A, B, D, and E are incorrect because they make statements that are not supported by the given information.

A Researcher Wishes to Determine Whether People with High Blood