EPID 301 Lecture Notes - Lecture 3: Sampling Frame, Simple Random Sample, Standard Deviation
7 Jul 2018
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**important to know the how to get the total person time at risk . What is the incidence density/rate? (total is 83 months/ textbook error= 82!) # new cases or events =3 (person 7 counts for 2 events) Incidence density = 3/83 person-months = 0. 036 per person month = 0. 4 per person year. What is the incidence density/rate? (book says to assume jan event for person #1 is. # new cases or events = 12 / incidence density = 12/108 person-months = 0. 111 per person-month = 1. 33 per person-year. If: distribution of the categories difers between the populations you are comparing, the rate of disease varies across the categories, The diference you see may be due to the variable that you categorized by and not the membership in one population or the other per se. A crude measure is really a weighted average of the speciic measures:
