Question

Assume that on average fraternal twins (two fertilized eggs and then could be of different sex) occur once in 150 births and identical twins (single egg divides into two separate embryos, so both have the same sex) once in 400 births (Note! This is not the true value). American male singer-actor Elvis Presley (1935-1977) had a twin brother who died at birth. Assume that an equal number of boys and girls are born on average. What is the probability that Elvis was an identical twin? Show the steps how you derived the equations to compute that probability. Implement this as a function in R that computes the probability given fraternal and identical twin probabilities. Below is an example of how the functions should be named and work if you want to check your result.

Answer 1

To compute the probability that Elvis was an identical twin, we can use conditional probability. P(A|B) = P(A and B) / P(B), where A represents Elvis being an identical twin and B represents Elvis having a twin brother who died at birth. Using the given probabilities, the calculated probability is 0.375.

Step-by-step explanation:

To compute the probability that Elvis was an identical twin, we can use conditional probability.

Let's define:

• Event A: Elvis was an identical twin
• Event B: Elvis had a twin brother who died at birth

We want to find P(A|B), the probability that Elvis was an identical twin given that he had a twin brother who died at birth.

Using conditional probability formula, P(A|B) = P(A and B) / P(B)

In this case, P(A) = 1/400 (probability of identical twins) and P(B) = 1/150 (probability of having a twin brother who died at birth)

Therefore, P(A|B) = (1/400) / (1/150) = 150/400 = 0.375