# Filename: TaySachs.R
# R script for determining P(A|not B) where
# A = offspring is a carrier
# B = offspring does have TaySachs
# given that both parents are carriers
# We'll need the function from OneChild.R
source("OneChild.R")
# Set how many times to run the experiment
N = 1000
# Set variables to sum up the probabilities of events
A = 0 # probability of Aa or aA
B = 0 # probability of aa
# Run set of N experiments N times
for (i in 1:N) {
# Set counters
a = 0 # heterozygous counter
b = 0 # homozygous recessive counter
# Run experiment N times
for (j in 1:N) {
# Get child's genotype if both parents are carriers
child = OneChild(1,1)
# Increase appropriate counter
if (child == 1) {
a = a + 1
} else if (child == 3) {
b = b + 1
} else {
# do nothing
}
}
# Add the probabilities for this set of N experiments
# to the running sum
A = A + a/N
B = B + b/N
}
# Estimated Probability of Event A
PA = A/N
# Estimated Probability of Event NOT B
PB = 1 - B/N
# Print out results
cat(sprintf("P(carrier|no disease)=%6.4f", PA/PB), "\n")