Final answer:
In sampling without replacement from a pool of 150 employees, the probability of selection for each individual changes with each draw. The chance improves from 1/150 for the first draw to 1/121 by the 30th draw due to the reduction of the total pool size after each selection.
Step-by-step explanation:
When a manager wants to draw a sample without replacement from a larger population, the probability of being selected changes with each draw. Initially, in our case of 150 employees, any given individual has a 1 in 150 chance of being chosen. However, as each person is selected, the total number of individuals remaining decreases, thereby increasing the odds that any given remaining individual will be the next chosen. For the first person picked, the chance is 1/150; for the second, 1/149; and this pattern continues, with the chances improving to 1/121 by the time the 30th person is selected.
This phenomenon occurs because the sampling method is without replacement, meaning once an employee is selected, they are not put back into the pool of potential candidates, reducing the total pool size each time. The decrease in the number of remaining individuals to select from directly influences the probability for the subsequent selections.