Question

11. Suppose in our Biostatistics 310 class of 139 students where no students had the flu when the fall quarter started, 2 students got the flu during the third week, 4 got the flu during the fifth week, and 16 got the flu during the eighth week. Six students dropped the class at the end of the fourth week, and we don't know whether or not they got the flu by the end of the quarter. The remaining students did not get the flu during the quarter. For the purpose of this problem, assume there are 10 full weeks in the fall quarter and that the strain of flu is so bad that once a student gets the flu, they still have it at the end of the quarter. A. *(1 point) Calculate the incidence rate for the flu in our Biostatistics 310 population. B. *(1 point) Can you calculate the 3rd week cumulative incidence of the flu in our Biostatistics 310 population? (By the 3rd week, we mean at the end of week 3.) If so, what is it? If not, why not? C. *(1 point) Can you calculate the 10th week cumulative incidence of the flu in our Biostatistics 310 population? (By the 10th week, we mean at end of 10 weeks.) If so, what is it? If not, why not? D. Suppose the reason the 6 students dropped the class was because they were starting to feel sick. How might this affect your interpretation of the incidence rate in part A?

Answer 1

Answer:

a)

Given,

To determine the incident rate

Here n = 310 class of 139

X1 = 2 , X2 = 4 , X3 = 16 , X4 = 6

Incident rate = (X1 + X2 + X3)/n * 1000

= (2 + 4 + 16) / 139 * 1000

= 22/139 * 1000

= 0.1583 * 1000

= 158.3

b)

Here we can say , yes the third week cumulative incidence of flue in Biostatistics 310 population is

X1 + X2 + X3

= 2 + 4 + 16

= 22

c)

Yes,' Tenth week cumulative incidence = 22

d)

If 6 students were dropped then the incident rate = (X1 + X2 + X3 + X4)/n * 1000

= (2+4+16+6)/139 * 1000

= 28/139 *1000

= 0.20144*1000

= 201.44

Here we can say that the incident rate is increased when 6 students dropped the class was due to that they were starting to feel sick