The u. s. national highway traffic safety administration gathers data concerning the causes of highway crashes where at least one fatality has occurred. from the 1998 annual study, the following probabilities were determined (bac is blood-alcohol level): p(bac=0|crash with fatality)=0.646 p(bac=0|crash with fatality)=0.646 p(bac is between .01 and .09|crash with fatality)=0.322 p(bac is between .01 and .09|crash with fatality)=0.322 p(bac is greater than .09|crash with fatality)=0.032 p(bac is greater than .09|crash with fatality)=0.032 suppose over a certain stretch of highway during a 1-year period, the probability of being involved in a crash that results in at least one fatality is 0.027. it has been estimated that 15% of all drivers drive while their bac is grater than .09. determine the probability of a crash with at least one fatality if a driver drives while legally intoxicated (bac greater than 0.09).

In january 2010, you began a one-year study of tuberculosis (tb) in a subsidized housing community in the lower east side of new york city. you enrolled 500 residents in your study and checked on their tb status on a monthly basis. at the start of your study on january 1st, you screened all 500 residents. upon screening, you found that 30 of the healthy residents had been vaccinated for tb and therefore were not at risk. another 20 residents already had existing cases of tb on january 1st. on february 1st, 5 residents developed tb. on april 1st, 10 more residents developed tb. on june 1st, 10 healthy residents moved away from new york city and were lost to follow-up. on july 1st, 10 of the residents who had existing tb on january 1st died from their disease. the study ended on december 31, 2010. assume that once a person gets tb, they have it for the duration of the study, and assume that all remaining residents stayed healthy and were not lost to follow-up. is the subsidized housing community in the lower east side of new york city a dynamic or fixed population? briefly explain the rationale for your answer. dynamic population it can changeable people can move out and move in into the population of a subsidized housing what was the prevalence of tb in the screened community on january 1st? prevalence = 30/500 0.06= 6% what was the prevalence of tb on june 30th? prevalence= 40/450=0.08= 8.88% what was the cumulative incidence of tb over the year? cumulative incidence = number of new cases/number in candidate population)over specified time period 10/450 = 2.2% suppose that you wanted to calculate the incidence rate of tb in the study population. calculate the amount of person-time that would go in the denominator of this incidence rate. be sure to show your work.