The time (in years) after reaching age 60 that it takes an individual to retire is approximately exponentially distributed with a mean of about five years. Suppose we randomly pick one retired individual. We are interested in the time after age 60 to retirement.
- Define the random variable. X = _________________________________.
- Is X continuous or discrete?
- X ~ = ________
- μ = ________
- σ = ________
- Draw a graph of the probability distribution. Label the axes.
- Find the probability that the person retired after age 70.
- Do more people retire before age 65 or after age 65?
- In a room of 1,000 people over age 80, how many do you expect will not have retired yet?
OpenStax Statistics, 5.3 The Exponential Distribution (Optional), exercise 47