Module 2 Lesson - CHLH 274 Final
Exam and All Correct Answers 2025-
2026 Updated.
four key mathematical terms are introduced - Answer • Ratio, Proportion, Percentage, Rate
• All are related to basic epidemiologic measures pertaining to:
• Frequency of disease in populations
• Risks associated with exposures to disease agents
counting and tabulating cases - Answer • Data cleaning: the review of data for accuracy and
completeness
• A clean data set contains a group of data that are ready for coding and analysis
graphical presentations - Answer • Used to summarize key aspects of the data set
• Types of graphs:
∙ bar graphs
∙ line graph
∙ pie chart
bar chart - Answer Type of graph that shows the frequency of cases for categories of a
categorical (discrete) variable such as a Yes/No variable
histogram - Answer • Like a bar chart
• Used for continuous variables
∙ Continuous - could have an infinite number of values along a continuum
∙ Ex: height, weight, blood sugar level
line graph - Answer Display trends, e.g., time trends
pie chart - Answer A circle that shows the proportion of cases according to several categories
mathematical epidemiology terms - Answer • Ratio
• Proportion
• Percentage
• Rate (can be crude, specific, or adjusted)
, ratio (R)
→ info from table - Answer ∙ R = X/Y
∙ X and Y can be any number, including ratio
rate (r)
→ info from table - Answer ∙ r= X/∆t
∙ type of ratio where the numerator is usually a count, and the denominator is time elapsed
proportion (p)
→ info from table - Answer ∙ p = A/A+ B
∙ type of ratio where the numerator is part of the denominator
percept (P)
→ info from table - Answer ∙ P = (A/A+B) x 100
∙ a proportion is multiplied by 100
ratio definition - Answer the value obtained by dividing one quantity by another
ratio examples - Answer rate, proportions, percentages
ex ratio calculation - Answer • With respect to AIDS mortality, the sex ratio of deaths (male
to female deaths) = X/Y, where:
∙ X = 450,451
∙ Y = 89,895
• The sex ratio = 450,451/ 89,895 = 5 to 1 (approximately)
proportion definition - Answer a type of ration in which the numerator is part of the
denominator (may be expressed as a percentage)
ex proportion - Answer Calculate the proportion of deaths from AIDS that occurred among
males
∙A
→ number of deaths from AIDS among male = 450,451
∙B
→ number of deaths from AIDS among females = 89,895
Exam and All Correct Answers 2025-
2026 Updated.
four key mathematical terms are introduced - Answer • Ratio, Proportion, Percentage, Rate
• All are related to basic epidemiologic measures pertaining to:
• Frequency of disease in populations
• Risks associated with exposures to disease agents
counting and tabulating cases - Answer • Data cleaning: the review of data for accuracy and
completeness
• A clean data set contains a group of data that are ready for coding and analysis
graphical presentations - Answer • Used to summarize key aspects of the data set
• Types of graphs:
∙ bar graphs
∙ line graph
∙ pie chart
bar chart - Answer Type of graph that shows the frequency of cases for categories of a
categorical (discrete) variable such as a Yes/No variable
histogram - Answer • Like a bar chart
• Used for continuous variables
∙ Continuous - could have an infinite number of values along a continuum
∙ Ex: height, weight, blood sugar level
line graph - Answer Display trends, e.g., time trends
pie chart - Answer A circle that shows the proportion of cases according to several categories
mathematical epidemiology terms - Answer • Ratio
• Proportion
• Percentage
• Rate (can be crude, specific, or adjusted)
, ratio (R)
→ info from table - Answer ∙ R = X/Y
∙ X and Y can be any number, including ratio
rate (r)
→ info from table - Answer ∙ r= X/∆t
∙ type of ratio where the numerator is usually a count, and the denominator is time elapsed
proportion (p)
→ info from table - Answer ∙ p = A/A+ B
∙ type of ratio where the numerator is part of the denominator
percept (P)
→ info from table - Answer ∙ P = (A/A+B) x 100
∙ a proportion is multiplied by 100
ratio definition - Answer the value obtained by dividing one quantity by another
ratio examples - Answer rate, proportions, percentages
ex ratio calculation - Answer • With respect to AIDS mortality, the sex ratio of deaths (male
to female deaths) = X/Y, where:
∙ X = 450,451
∙ Y = 89,895
• The sex ratio = 450,451/ 89,895 = 5 to 1 (approximately)
proportion definition - Answer a type of ration in which the numerator is part of the
denominator (may be expressed as a percentage)
ex proportion - Answer Calculate the proportion of deaths from AIDS that occurred among
males
∙A
→ number of deaths from AIDS among male = 450,451
∙B
→ number of deaths from AIDS among females = 89,895
