HLTH 501 BIOSTATISTICS FINAL EXAM 2021
PRACTICE TEST 2026 TESTED QUESTIONS
WITH ANSWERS GRADED A+
⩥ Sensitivity. Answer: The probability of a positive test in those with the
disease.
Calculated by a/(a+c)
⩥ Specificity. Answer: Ability of a test to detect non-disease when no
disease is present.
Calculated by d/(b+d)
⩥ Predictive values. Answer: The probability of having the disease being
tested for if the test result is positive and the probability of not having
the disease being tested for if the result is negative.
⩥ Positive predictive value (PPV). Answer: The probability that a
positive test result truly indicates the presence of disease.
PPV = a/(a+b)
, ⩥ Prevalence. Answer: Probability of the disease.
Prevalence = (a+c)/(a+b+c+d)
⩥ Negative predictive value (NPV). Answer: The probability that a
negative test result truly indicates the absence of disease.
NPV = d/(b+d)
⩥ Odds ratio (OR). Answer: Measure of association between two
different properties in a population. Tells how the presence or absence of
one property may have an effect on the other.
OR is also used to determine if a particular exposure is a risk factor for a
particular outcome.
⩥ Odds ratio interpretation. Answer: OR = 1 means exposure A does not
affect the odds of property B.
OR = more than 1 means there are higher odds of property B happening
with exposure to property A
OR = less than 1 means there are lower odds of association
⩥ Dichotomous variables. Answer: Nominal measure with two
outcomes.
PRACTICE TEST 2026 TESTED QUESTIONS
WITH ANSWERS GRADED A+
⩥ Sensitivity. Answer: The probability of a positive test in those with the
disease.
Calculated by a/(a+c)
⩥ Specificity. Answer: Ability of a test to detect non-disease when no
disease is present.
Calculated by d/(b+d)
⩥ Predictive values. Answer: The probability of having the disease being
tested for if the test result is positive and the probability of not having
the disease being tested for if the result is negative.
⩥ Positive predictive value (PPV). Answer: The probability that a
positive test result truly indicates the presence of disease.
PPV = a/(a+b)
, ⩥ Prevalence. Answer: Probability of the disease.
Prevalence = (a+c)/(a+b+c+d)
⩥ Negative predictive value (NPV). Answer: The probability that a
negative test result truly indicates the absence of disease.
NPV = d/(b+d)
⩥ Odds ratio (OR). Answer: Measure of association between two
different properties in a population. Tells how the presence or absence of
one property may have an effect on the other.
OR is also used to determine if a particular exposure is a risk factor for a
particular outcome.
⩥ Odds ratio interpretation. Answer: OR = 1 means exposure A does not
affect the odds of property B.
OR = more than 1 means there are higher odds of property B happening
with exposure to property A
OR = less than 1 means there are lower odds of association
⩥ Dichotomous variables. Answer: Nominal measure with two
outcomes.
