Surveillance and Epidemiologic Investigation

Question 1

WIdentify the median in the following list of numbers: 6, 2, 9, 7, 1, 4

Answer 1

5

Question 2

What type of error occurs when someone rejects the null hypothesis but the null hypothesis is true?

Answer 2

Type I error (false positive)

Question 3

For which of the following procedure(s) is the surveillance period for deep incisional or organ/space SSI 90 days? 1) Cesarean section 2) Craniotomy 3) Coronary artery bypass graft 4) Laminectomy

Answer 3

2, 3 - Craniotomy, Coronary artery bypass graft

Question 4

What is an appropriate indicator to monitor process compliance?

Answer 4

Appropriate antibiotic dosage

Question 5

The ongoing collection, collation, and analysis of data and the ongoing dissemination of information to those who need to know so that action can be taken

Answer 5

Surveillance

Question 6

What does it mean when a journal article states that the data the authors collected are normally distributed?

Answer 6

The mean, median and mode of the data are equal (and the curve will have a bell shape)

Question 7

Pain at the incision site 10 days after a breast reduction procedure and drainage is culture-positive for methicillin-susceptible S. aureus (MSS) is indicative of what?

Answer 7

Superficial SSI

Question 8

What information is needed to calculate a CLABSI rate for the ICU?

Answer 8

The number of patients who had bloodstream infections identified and the number of device days for the time period

Question 9

What type of rate would the IP want to calculate to give feedback to the surgeons at her facility?

Answer 9

Provider-specific

Question 10

The process of benchmarking data should include:

Answer 10

Standardized definitions used consistently; Adequate training of personnel to collect, store, manage, and analyze data; data are calculated using the same methodology as a nationally validated system.

Question 11

When can a chi-square test be used?

Answer 11

To evaluate the effect of a variable on outcomes, to calculate an odds ratio or relative risk, and if each cell of the table is greater than 5.

Question 12

What measure of central tendency is most affected by outliers?

Answer 12

The mean

Question 13

What does the p value in statistical test results indicate?

Answer 13

The probability of having committed a Type I error

Question 14

On a normally distributed data set, what percentage of values lies within three standard deviations from the mean?

Answer 14

99.7%

Question 15

What statistical test is used when the data are small in numbers?

Answer 15

Fisher’s exact

Question 16

What are statistical process control (SPC) charts used for?

Answer 16

Monitoring the process of care, facilitating the determination of variation, and monitoring outcomes.

Question 17

How do you find the incidence rate?

Answer 17

The number of new cases per population at risk in a given time period.

(New cases/Total number of patient days) X 1,000

Question 18

What does ‘endemic’ mean?

Answer 18

An expected number of cases occurs each year in a given geographical area

Question 19

How does a pandemic differ from an epidemic?

Answer 19

Several countries or continents are involved

Question 20

How is specificity of a test for infection or disease calculated?

Answer 20

The number of true negatives divided by the total number of persons without disease, times 100.

Question 21

A measure of dispersion that reflects the variability in values around the mean

Answer 21

Standard deviation

Question 22

In any normal distribution, the proportion of observations that are within two standard deviations of the mean is closest to:

Answer 22

0.95

Question 23

What is the most important feature of nonparametric tests?

Answer 23

They make no assumption about variance in the populations

Question 24

Which of the following indicates a strong positive correlation? a) r=0 b) r=-0.993 c) r = 0.603 d) r=0.45

Answer 24

C) r = 0.603

Question 25

Which of the following steps are not included in hypothesis testing? a) State the null and alternative hypotheses b) Set the significance level c) Eliminate outliers d) Compare the probability value to the significance level

Answer 25

C) Eliminate outliers

Question 26

What is the range of the correlation coefficient?

Answer 26

-1 to 1

Question 27

If the index of kurtosis is -1.99, then the curve is:

Answer 27

Relatively flat

Question 28

The probability or likelihood of an event occurring is the:

Answer 28

Risk

Question 29

A table is used to illustrate data:

Answer 29

Arranged in rows and columns

Question 30

The value that appears most frequently within a set of numbers

Answer 30

Mode

Question 31

As the sample size increases, how is the power of the study affected?

Answer 31

Power is increased

Question 32

What is the term for an extraneous variable that systematically varies with the independent variable and influences the dependent variable?

Answer 32

Confounding variable

Question 33

Properties of a normal distribution:

Answer 33

-Forms a symmetric bell-shaped curve -50% of the scores lie above and 50% below the midpoint of the distribution -Mean, median and mode are located at the midpoint of the x axis

Question 34

What are the criteria for causality?

Answer 34

-The incidence of disease is higher in those who are exposed to the factor -Evidence that the independent and dependent variables are related -The association has been observed in numerous studies

Question 35

A frequency polygon:

Answer 35

Is useful for showing two sets of data on a single graph and uses connecting lines and data points

Question 36

What does targeted surveillance focus on?

Answer 36

Tracking high-risk, high-volume procedures and potentially preventable healthcare-associated infections (HAIs)

Question 37

What virus is the causative agent in Kaposi's sarcoma?

Answer 37

Human herpesvirus 8

Question 38

T/F: Up to 50 percent of people in endemic areas have been exposed to Coccidioides spores.

Answer 38

True

Question 39

What would need to be calculated if you wanted to know the proportion of a disease that could be prevented by eliminating the exposure in the entire study population?

Answer 39

Population attributable risk percent

Question 40

The precision of an estimate of a relative risk depends on:

Answer 40

Size of the study

Question 41

What is a causal web?

Answer 41

The web of causation refers to the interrelationship of multiple factors that contribute to the occurrence of a disease

Question 42

What happens when the prevalence of a disease is very low?

Answer 42

The positive predictive value of a diagnostic test is lowered

Question 43

Which group of viruses are the most common cause of epidemic gastroenteritis worldwide?

Answer 43

Noroviruses

Question 44

How do you calculate attributable risk (AR)?

Answer 44

AR = IE - IU Incidence in exposed - Incidence in unexposed

Question 45

How do you calculate incidence?

Answer 45

Number of cases / Total population at risk

Question 46

T/F: IBD is associated with increased morbidity and mortality associated with CDI.

Answer 46

True

Question 47

What might be the most cost-effective approach for screening for TB/airborne diseases among homeless individuals?

Answer 47

Screening for TB with chest X-ray

Question 48

How do you calculate the odds ratio?

Answer 48

The odds ratio (also called the cross-product ratio) is the probability of having a particular risk factor if a condition or disease is present divided by the probability of having the risk factor if the disease or condition is not present (ad/bc)