Lisa Garrett has been a shift scheduler at a local fast-food chain for the past three years. Although the restaurant’s patronage is relatively stable, employee attendance is not. For the most part the restaurant employs students from a nearby high school. Experience has taught Lisa that both the age of the employee and the season of the year affect the reliability of employee attendance. During the school year, seniors are the most responsible and report to work 97% of the time, whereas juniors report only 95% of the time, and sophomores report 90% of the time. After graduation, however, students’ thoughts turn to fun and freedom, and everyone’s attendance drops to 90%.
a. If a shift consists of two seniors, one junior, and one sophomore, what is the probability that Lisa will be able to operate with a full shift during the school year? During the summer months?
b. Suppose during the summer months, Lisa can find replacement workers 90% of the time. However, during the school year, she is successful only 80% of the time. How do replacement workers improve shift reliability during the summer months? During the school year?
c. Restaurant management recognizes supervisors with a Super Fry award if shifts are completely staffed over 95% of the time. Does Lisa qualify for a Super Fry?