Tumor counts: A cancer laboratory is estimating the rate of tumorigenesis in two strains of mice, A and B. They have tumor count
data for 10 mice in strain A and 13 mice in strain B. Type A mice have been well studied, and information from other laboratories suggests that type A mice have tumor counts that are approximately Poisson-distributed with a mean of 12. Tumor count rates for type B mice are unknown, but type B mice are related to type A mice. The observed tumor counts for the two populations are
The observed tumor counts for the two populations of mice are:
Type A mice = 10 * 12 = 120 counts
Type B mice = 13 * 12 = 156 counts
Step-by-step explanation:
Since type B mice are related to type A mice and given that type A mice have tumor counts that are approximately Poisson-distributed with a mean of 12, we can then assume that the mean of type A mice tumor count rate is equal to the mean of type B mice tumor count rate.
This is because the Poisson distribution can be used to approximate the the mean and variance of unknown data (type B mice count rate) using known data (type A mice tumor count rate). And the Poisson distribution gives the probability of an occurrence within a specified time interval.
to go through the origin, it must pass through (0,0); thus if we plug in 0 for x and 0 for y we are left with 4 + 12(z) = 0, solve for z and we get -1/3
