A hip joint replacement part is being stress-tested in a laboratory. Let us define
We want to find the probability that exactly two of the 11 parts successfully complete the test. A random variable X is said to follow binomial distribution if it assumes only non-negative values and its probability mass function is given by:
Here we choose 11 randomly and independently parts. Therefore,
Now using the binomial probability we have the probability that exactly two of the 11 parts successfully complete the test is
Result: