Statistics NAVLE

Question 1

What does PPV stand for in the context of test statistics?

Answer 1

Positive Predictive Value

PPV indicates the proportion of test-positive animals that are truly infected or disease positive.

Question 2

What is the NPV in test statistics?

Answer 2

Negative Predictive Value

NPV indicates the proportion of test-negative animals that are truly not infected or disease negative.

Question 3

What are the FIP test stats for Mɸ’s in effusion fluid?

Answer 3

• 100% PPV
• 57% NPV

These statistics indicate the effectiveness of the test in identifying true positives and negatives.

Question 4

What is the PPV for anti-coronavirus antibodies in serum?

Answer 4

0.44

This indicates a low positive predictive value for this specific test.

Question 5

What is the NPV for anti-coronavirus antibodies in serum?

Answer 5

0.94

This indicates a high negative predictive value for this specific test.

Question 6

What is the Pyramid of Evidence used for?

Answer 6

• Filtered evidence: systematic reviews, meta-analyses, critical appraisals
• Unfiltered evidence: randomized controlled trials, cohort studies, case reports

The pyramid illustrates the hierarchy of evidence in research.

Question 7

What does specificity measure in a test?

Answer 7

Proportion of non-diseased animals identified as negative

Specificity can be affected by factors such as cross-reactivity and sample contamination.

Question 8

What is the formula for calculating specificity?

Answer 8

Specificity = True negatives / (True negatives + False positives)

This formula helps determine the accuracy of a test in identifying non-diseased individuals.

Question 9

What does sensitivity measure in a test?

Answer 9

Proportion of diseased animals identified as positive

Sensitivity can be low when there are very few amounts of the target measure or when samples are degraded.

Question 10

What is the formula for calculating sensitivity?

Answer 10

Sensitivity = True positives / (True positives + False negatives)

This formula helps determine the accuracy of a test in identifying diseased individuals.

Question 11

Define false positives.

Answer 11

Non-diseased animal that tests positive

This indicates a test error where a healthy individual is incorrectly identified as having the disease.

Question 12

Define false negatives.

Answer 12

Diseased animal that tests negative

This indicates a test error where an infected individual is incorrectly identified as healthy.

Question 13

What is the prevalence formula?

Answer 13

Prevalence = Total Disease / Total * 100

This formula calculates the proportion of a population that has a specific disease at a given time.

Question 14

What are the characteristics of a cohort study?

Answer 14

Addresses temporality of disease causation

In cohort studies, exposure must precede the disease.

Question 15

What is a case-controlled study?

Answer 15

Compares diseased individuals with non-diseased subjects regarding exposure to a factor

This study design is also known as retrospective.

Question 16

What is a cross-sectional study?

Answer 16

Compares two groups based on disease status regarding exposure status

This study design assesses the relationship between exposure and outcome at a single point in time.