Sensitivity/Specificity — Flashcards

Flashcard 1: Under Hardy-Weinberg conditions, what is the expected frequency of an X-linked recessive disease in males? Females?

Answer: males - q females - q2 (if condition is survivable)

Flashcard 2: coefficient of determination (r2) (biostatistics)

Answer: measure of correlation 0 indicates no relationship 1 indicates perfect concordance

Flashcard 3: Pearson's correlation coefficient (r) (biostatistics)

Answer: measure of linear correlation -1 is perfect inverse relationship 1 is perfect direct relationship

Flashcard 4: What is the Chi-square (X2) test used for? (biostatistics)

Answer: compare proportions of categorical outcomes between two groups (not comparison of means!)

Flashcard 5: Which parameters, sens/spec or PPV/NPV are affected by prevalence of the disease in the population?

Answer: PPV/NPV

Flashcard 6: PPV (biostatistics)

Answer: Probability that a person actually has disease given a positive test result.

Extra: PPV = TP/(TP+FP)

Flashcard 7: NPV (biostatistics)

Answer: Probability that a person does not have disease given a negative test result.

Extra: NPV = TN/(TN+FN)

Flashcard 8: With increased prevalence, how are PPV and NPV changed? _____

Answer: PPV increases and NPV decreases

Extra:  https://onlinemeded.org?ref=anki 

Flashcard 9: In a Ratio of A/B, is A part of B? _____

Answer: No

Extra:  https://onlinemeded.org?ref=anki 

Flashcard 10: Which predictive value below is influenced by prevalence? _____

Answer: PPV/NPV (Predictive values)

Extra:  https://onlinemeded.org?ref=anki