Reference no: EM131755005

Advanced Epidemiology and Biostatistics for Nursing Final Examination:

Q1. Which of the following best describes the design where subjects are sampled by disease status and is often used when the investigator is interested in rare diseases? (Choose one best answer and provide rationale).

A. intervention trial

B. retrospective cohort

C. ecologic study

D. case control study

E. none of the above

Q2.  The evidence supporting obesity as a risk factor for colon cancer remains inconclusive, especially among women. A study reported the association between obesity (measured at baseline) and colon cancer morbidity as determined from review of medical records and death certificates in a nationally representative cohort of men and women age 25-74 years who participated in the First National Health and Nutrition Examination Survey from 1971 to 1975 and were subsequently followed up through 1992. The following table 1 is from this study for men and women combined.

Table 1. Incidence of colon cancer, First National Health and Nutrition Examination Survey from 1971 to 1975 with follow-up 1992.

Baseline body mass index*	Number of incident cases of colon cancer	Person-years of follow up
<22	30	53,470
22 - <24	48	38,910
24 - <26	29	36,610
26 - <28	56	32,630
28 - <30	33	21,120
30+	49	34,900

* kg body weight per height in meters squared

a. Which of the following best describes the research design used in this study? (Choose one best answer).

A. Cross-sectional survey

B. Ecological study

C. Population based case control study

D. Cohort study

E. None of the above

b. Calculate the relative risk (RR) of colon cancer associated with a BMI of 28 - <30 using the lowest BMI category as referent. In one sentence, interpret your answer.

Q3. Y represents the predicted value of y calculated using the equation Y = a + bX. In the formula, SBP = 88 + 2.6 X; where X = value of postnatal age (hours) for the neonates ≤ 1,000 grams?

a. What is the value of the intercept (a)?

b. Interpret the value of the intercept?

c. What is the value of the slope (b)?

d. Interpret the value of the slope?

Q4. The strength of an association is one of the criteria for evaluating the cause and effect relationship between an exposure and outcome. Which of the following is a measure of the strength of association? (Choose one best answer and provide rationale).

A. odds of disease among exposed relative to the prevalence of exposure in the source population

B. cumulative incidence among the exposed

C. the ratio of odds of exposure among cases to the odds of exposure among the non-cases

D. incidence rate among the exposed

E. none of the above

Q5. What is the dependent variable(s) in the research question "Is the quality of life of nursing home residents affected by their functional ability or hearing acuity"?

A. Quality of life

B. Functional ability

C. Hearing acuity

D. Nursing home residents

Q6. Among 400 persons with negative screening tests for HIV antibody, 220 are negative with HIV virus.

A. The most appropriate measure is:

a. sensitivity

b. specificity

c. predictive value positive  

d. predictive value negative

B. Estimate the value of this measure and interpret it:

Q7. Please interpret the following: "A study showed that the attribute able fraction of the exposure to smoking is 80%".  What is the implication of this indicator on nursing?

Q8. Tell whether the following statement is true or false:

A. Outcome research examines the quality and effectiveness of health care and nursing services.

B. Reliability is the degree to which an instrument measures what it is supposed to measure.

C. Researchers usually sample from the target population.

D. Point estimation through statistical procedures enables researchers to make objective decisions about the validity of their hypotheses.

E. Internal consistency reliability is the extent to which the different items of the scale are not reliably and consistently measuring attribute.

Q9. Discuss the difference between efficacy, effectiveness, and efficiency. Give examples.

Q10. What are the criteria for a successful screening program?

Q11. The overall odds ratio for the association between breast cancer and smoking status is 2.1 (95% confidence interval=1.3-3.6).

a- Interpret the odds ratio and the 95% confidence interval.

b- What do you conclude about smoking - is it a possible risk or preventive factor? Provide rationale.

Q12. Use the following diagram to answer questions A to C.

A. The study design is: ____________________________ (Provide rationale)

B. In this study:

1. The exposure (independent variable) is:   ______

2. The outcome (dependent variable) is:____________

C. The measure of association in this study is:______________

Q13. A distribution of data values can be described in terms of all of the following characteristics except:

a. Central tendency

b. Shape

c. Relative standing

d. Variability

Q14. What is the best measure to estimate the percent of children with otitis media that have abnormal otoscope examination? Please explain.

a. Case fatality

b. Specificity

c. Sensitivity

d. Incidence rate

e. Risk

Q15. Which of the following statements about R2 is not true?

a. It is sometimes called the coefficient of determination.

b. Its value indicates percentage of variation of Y explained by all predictors as a set.

c. It is a measure of magnitude but not direction of relationships.

d. Its values can range from -1.00 to +1.00.

Q16.  Which of the following approaches can be used to compare the relative benefits of two alternative pharmacologic treatments for chest disease?

a. screening         

b. randomized controlled clinical trial 

c. cohort study

d. case-control study   

Q17. Regression is used to:

a. Corroborate results from a correlation analysis

b. Determine the magnitude of effects of correlations among variables

c. Estimate sample size needs when planning a study involving correlation

d. Make predictions about values for a variable based on known values for another

Q18. A researcher found a correlation of -.28 between scores on a self-esteem scale and number of alcoholic drinks consumed in the prior month. What does this mean?

a. People who drank more alcohol had a slight tendency to have higher self-esteem.

b. People who drank more alcohol had a slight tendency to have lower self-esteem.

c. Drinking more alcohol tended to cause lower self-esteem.

d. Having lower self-esteem tended to cause people to drink more alcohol.

Table 2. Odds Ratios for Late Extubationa after Cardiac Surgery, by Patient Characteristics (N = 673)

	Extubation < 5 Hours (%)	Extubation > 5 Hours (%)	OR	95% CI
Female patient	19.2	29.8	1.66	1.14 - 2.60
White patient	89.6	91.3	1.09	0.80 - 1.21
Hypertensive	62.7	73.9	1.58	1.09 - 2.24
Prior CABG	9.4	16.0	2.03	1.22 - 3.65

^aLate extubation = More than 5 hours of mechanical ventilation

Q19. Refer to Table 2 above. Which of the following numbers is a point estimate for a risk index for delayed extubation?

a. 19.2

b. 29.8

c. 2.03

d. 1.14

e. None of the above

Q20. Refer to Table 2 above. Which patient characteristic was most associated with a higher risk of delayed extubation?

a. Sex

b. Race

c. Prior experience with CABG

d. Hypertensive status

Q21. If the mean µ = 64.5 and the standard deviation s = 2.5. What is the probability, if we pick one man at random, that his height will be between 65 and 74 inches P(65 < X < 74)?  Show the calculation and interpret the results.

Q22. What is a multiple regression equation? (Select all that apply.)

A. One that represents the mathematical effect that several independent variables have on the dependent variable

B. One in which the x-values are multiplied by one another

C. One that explains more of the variance in y than does a single linear regression equation

D. An experimental model for determining best practices

E. One that uses more than one predictor variable to predict the value of the outcome variable

F. One that explains all of the variance in the dependent variable, in terms of several independent variables

Q23. Which is the best statement that differentiates between the sizes of samples and populations?

a. A sample has a maximum size; a population does not.

b. A sample cannot be the same size as a population.

c. If a person is a member of a population, he or she is a member of the sample chosen from that population.

d. A population is usually larger than a sample.

Q24. Which of the following items is different when comparing probability sampling and non-probability sampling?

a. The type of descriptive statistics applied to the sample

b. The size of the sample

c. The relative chance of being selected as a study participant

d. Whether or not the findings can be generalized

Table 3. Physiologic Outcomes for Patients with Emphysema during Exercise Performance Under Three Different Conditions (N = 50)

Physiologic Outcome	Control Condition   Mean + SD	With Admin-istration of Oxygen Mean  + SD	With Compressed Air Mean  + SD	F	p
Dyspnea rating (1-10)	4.70± 2.3	4.77 ± 2.6	5.09 ± 2.6	4.99	.008
Heart rate (bpm)	121.1 ± 13.6	126.9 ± 19.9	126.0 ± 21.1	12.54	<.001
Oxygen saturation, SPO2 (%)	91.0 ± 3.9	94.4 ± 4.0	89.9 ± 4.1	9.80	<.001
Breaths per minute	24.1 ± 4.8	24.3 ± 5.9	28.8 ± 6.5	1.86	.22

Q25. Refer to Table 3 above. For which outcome would the researcher need to accept the null hypothesis?

a. Dyspnea rating

b. Heart rate

c. Breaths per minute

d. Oxygen saturation

Q26.  The chi-square test is used to test the null hypothesis that:

a. The medians of groups being compared are equal

b. Two categorical variables are independent (not related)

c. The expected cell sizes are zero

d. The odds ratio is zero

Q27. The death rates from various conditions are often compared across geographic areas. These comparisons are usually based on directly age-standardized mortality rates. Which of the following best describes what is meant by an age-standardized rate created by the direct method? (Choose one best answer and provide rationale).

A. The number of events in each age stratum of a standard population is used to create a weighted average rate.

B. The event rates in each age stratum in the standard population are used to create a weighted average rate.

C. The event rates in the geographic area of interest are applied to the age-stratum sizes of a standard population to create a rate that is a weighted average.

D. The event rates in the geographic area of interest are compared to the event rates of a standard population to create a summary rate that is a weighted average.

Q28. Calculate the percentage of variance explained for correlation (r) = 0.90 [i.e., the coefficient of determination]. Is this correlation clinically important? Provide a rationale for your answer.

Q29. Consider two values, correlation ((r) = 0.04 and (r) = -0.75).

A. Describe the clinical importance of both (r) values.

30. What are the uses of factor analysis?

Q31. A researcher identifies three variables and formulates a hypothesis that links them. That hypothesis is testable. What does it mean that the hypothesis is testable?

a. All the variables in the hypothesis are measurable.

b. The hypothesis must be replaced by a research question.

c. The value of the hypothesis is low.

d. The hypothesis is causational.

Q32. Based on the data on table 4 below:

A. How many factors will be extracted? Provide justifications.

B. What percent of the variance the extracted factor(s) will explain? Provide justifications.

Table 4. Factor analysis

FACTORS	Eigen Value	Percent of Variance
1	2.21	37.8
2	2.12	34.3
3	.74	12.3
4	.43	7.2
5	.38	6.4
6	.12	2.0

Q33. Use the table below (Table 5. Component Matrix) and indicate the loading of the variables for each factor

Table 5. Component Matrix

	FACTOR 1	FACTOR 2
Q1	0.026	0.865
Q2	0.387	0.619
Q3	0.760	0.091
Q4	.651	0.396
Q5	0.030	0.634
Q6	0.805	-.064
Q7	0.399	0.651
Q8	-0.794	0.167
Q9	0.728	-0.097
Q10	-0.183	0.770

Extraction Method: Principal Component Analysis.

A. What are the specific questions that were represented in Factor I? Provide justifications.

Q34. Why is selection of an appropriate design for a research study important?

a. If the design is an incorrect one, the researcher will examine variables and their interactions in a way that does not answer the research question.

b. The design provides a blueprint or diagram that appears in the concept map.

c. If there is no design, critique is impossible.

d. If the design is appropriate, the researcher can eliminate error.

Q35. A researcher conducts research and uses a small sample that is not randomly selected. When he replicates the study, twice, he again uses the same site and another small sample that is not randomly selected. This is a threat to which type of validity?

a. Statistical conclusion validity

b. Internal validity

c. Construct validity

d. External validity

Q36. Consider two values, correlation ((r) = 0.04 and (r) = -0.75).

B. Describe the clinical importance of both (r) values.

Q37. Correlational research has which of the following characteristics? (Select all that apply.)

a. Examines the strength of a relationship, to determine causality

b. Allows independent variables to be manipulated

c. Examines relationships among existing variables

d. Is always used to generate rather than test hypotheses

e. Examines differences under at least two conditions

f. Is non-interventional

Q38. The calculated Pearson's r was -.95 in a research study on number of hours parents spent at children's sporting events and number of arrests those children had experienced by age 30. What does this Pearson's value signify? (Select all that apply.)

a. No relationship

b. Weak linear relationship

c. Moderate linear relationship

d. Strong linear relationship

e. Positive relationship

f. Inverse relationship

g. Negative relationship

Q39. An instrument with 12 questions [i.e., a scale of 12 variables] was evaluated for internal consistency (reliability). The following is the result:

Cronbach's Alpha             N of Items          

0.523                                      12         

Is the scale internally consistent? How can you improve the internal consistency? Provide rationale.