CBIC Statistics Exam Questions & Answers Correct 100%

Attack Rate - Answer is a special form of incidence rate. Is truly not a rate. Is a proportion of persons at risk. # of new cases/ population at risk x100 Prevalence (or Point Prevalence) Rate - Answer the proportion of persons in a population with a particular disease or attribute at a specific point in time. # active cases of HAI or # All HAIs up to a certain point. /total number x 1000 Basic Formula for all Types of Rates - Answer Rate= X/Y x K Mortality Rate - Answer is the measure of frequency of death in a defined population during a specific time. Crude Mortality : Dying from ALL CAUSES. Cause Specific Mortality Rate: specified cause for a population. X/Y X K Crude Mortality Rate - Answer X/Y X 1000= Cause Specific Mortality Rate - Answer X/Y X 100,000 Incidence density rate - Answer accounts for varying time periods of follow-up Usually used in a cohort studies of diseases with long incubation or latency periods, such as chronic diseases. # of cases (during observation period) /the time each person was observed (totaled for all persons) x 10. Relative Risk (Risk Ratio) - Answer Measure of the strength of association used in prospective and experimental studies. Used in cohort studies (a group of individuals who share a common experience ie: central lines) Is prospective, starts at point 0 and continues into the future. Asks the question: What is the risk of developing disease if exposed to the risk factor? Relative Risk - Answer Create a table, enter the known values, calculate and enter the unknown values, calculate a relative risk using formula RR= (A/R1)/C/R2) If RR=1 - Answer There is no significant association If RR1 - Answer there is a positive association (worse outcome) If RR 1 - Answer there is a negative association (protective) Odds Ratio - Answer another measure of association that is closely related to relative risk. Probability of having a particular risk factor if the disease or condition is present divided by the probability of having the risk factor if the disease or condition is not present. Odds Ratio - Answer Used with case control studies. Is retropective. Looks at prevalence. Sensitivity - Answer the probability of a positive test among patients WITH disease