The researcher hypothesizes that there will be a difference in mean PSA between the two groups. We are assuming that PSA levels have a symmetric distribution. The 95% confidence interval for the difference in mean PSA between age groups was (0.2, 6.0). What can you conclude from this confidence interval?
Group of answer choicesWe are 95% confident that the estimated mean PSA level for men aged ≤50 years is 0.2 and for men aged >50 years is 6.0.We are 95% confident that mean PSA levels between the two groups are the same.
We are 95% confident that the mean PSA levels between the two groups are different.
We do not have enough information to form a conclusion.
Flag question: Question 2Question 22 pts
Which of the following can be used to answer the question “How large is the difference between population means?”
Group of answer choicesp-valueConfidence interval
Independent samples t test
ANOVA
Flag question: Question 3Question 32 pts
Suppose that the overall F-test obtained from performing a one-way ANOVA resulted in a p-value that was not statistically significant. Which of the following CANNOT be true?
Group of answer choicesThe variability within the groups is very large compared to between-group variability.The variability between the groups is very large compared to within-group variability.
The ratio of the between and within variability was not sufficiently large.
The F-statistic was not larger than the critical value obtained from the F-distribution.
Flag question: Question 4Question 42 pts
An investigator wishes to determine if there are any differences in the level of blood pressure as a function of whether the person is sitting upright in a chair or lying down. Ten patients were selected to collect systolic blood pressure data in both the sitting and lying positions. Decide what statistical procedure would most likely be used to answer the research question. Assume all assumptions have been met for using the procedure.
Group of answer choicesOne sample t testTwo independent samples t test
Paired Samples t test
ANOVA
Flag question: Question 5Question 52 pts
Does mean blood pressure differ for seniors who are sedentary, a little active, and very active? Decide what statistical procedure would most likely be used to answer the research question. Assume all assumptions have been met for using the procedure.
Group of answer choicesOne sample t testTwo independent samples t test
Paired Samples t test
ANOVA
Question 6
A group of individuals were selected to participate in a diet program. Waist circumferences were collected before and after the program. The question of interest was whether there was a mean change in circumference due to the diet program. The researcher found a mean change of 2.2 inches and wants to conclude that the diet works. Can the researcher make this conclusion? Why or why not?
question 7
Suppose a 95% confidence interval for the mean change in waist circumference was calculated (-0.75, 5.15). Explain to the researcher what this means.
question 8
The national average for the time spent waiting in a doctor’s office is 18 minutes. You wish to test whether the time spent waiting in the doctor’s office where you work differs from the national value. You find the average time a patient spent waiting in the office was 20.2 minutes. Assuming normality, you conduct a one-sample t-test. You get a p-value of 0.12. Interpret the results. You need to write more than one sentence for your conclusion.
question 9
An investigator conducted an ANOVA where she was interested in the differences in mean blood pressure levels for three groups. The results are given in the table below.
a. What are the correct null and research hypotheses for this question?
b. What can the investigator conclude? You need to write more than one sentence for your conclusion.
Analysis of Variance
SourceDFSums of SquaresMean SquareF-valuep-valueModel28.1674.080.290.7546Error9126.514.05 Total11134.67 question 10
Researchers want to know if subjects who were diagnosed with hypertension (hyperten=1) at some point over the 24-year follow-up had a different mean BMI score (bmi1) at the initial exam than subjects who were not diagnosed with hypertension (hyperten=0).
a. What are the correct null and research hypotheses for this question?
b. The following output was obtained from SAS. What would our conclusion be based on this output for both tests that have been performed? You need to write more than one sentence for your conclusion.