Question

1. According to the Center for Disease Control and Prevention, the breast cancer rate for women has decreased at 0.9% per year between 2000 and 2009.

a. If 192,370 women were diagnosed with invasive breast cancer in 2009, how many were diagnosed in 2005? For this problem, assume that there is no change in population
from 2005 and 2009.
b. According to the American Cancer Society, in 2005 there were 211,240 people diagnosed with breast cancer. In a written response, communicate how precise and accurate your
solution in part
(a) is, and explain why

Answer 1

a. 199,389

b. b. From the part A, the question suggests a 0.9% yearly decrease which amounts to 199,389. This answer does not correspond to their recorded figure because the 0.9% decrease was just an average taken over the period. There could be years that the decrease was way smaller than the recorded average, thus using average may not be a good way for calculating population decrease over a period of time.

Explanation:

a. Population in 2009 = 192,370

This means that in 2005 the population = 192,370 x 1.009 x 1.009 x 1.009 x 1.009 = 199,389

b. From the part A, the question suggests a 0.9% yearly decrease which amounts to 199,389. This answer does not correspond to their recorded figure because the 0.9% decrease was just an average taken over the period. There could be years that the decrease was way smaller than the recorded average, thus using average may not be a good way for calculating population decrease over a period of time.