A companys personnel director surveyed employees about their satisfact...
To identify the assumption made by the personnel director, let's analyze each answer choice:
A. No other performance rating system is as good as the current system.
This assumption is not necessary for the personnel director's conclusion. The satisfaction of employees with the current system does not necessarily depend on the comparison with other systems. The conclusion is specifically about the relationship between high-rated employees and their satisfaction with the current system, rather than a comparison with alternative systems.
B. The company's best-performing employees received high ratings.
This assumption is necessary for the personnel director's conclusion. If the best-performing employees did not receive high ratings, then the correlation between high ratings and satisfaction with the system would not hold, and the conclusion that the company's best-performing employees liked the system would be undermined.
C. Employees who received low ratings were dissatisfied with the system.
This assumption is not necessary for the personnel director's conclusion. The conclusion is about the satisfaction of high-rated employees, not the dissatisfaction of low-rated employees. The data from the survey only address the satisfaction of high-rated employees, and the conclusion does not depend on the satisfaction levels of low-rated employees.
D. Employees who receive high ratings from a performance-rating system will like that system.
This assumption is not necessary for the personnel director's conclusion. The conclusion is specifically about the satisfaction of employees who received high ratings, but it does not make a general claim that all employees who receive high ratings will like the system. The conclusion is based on the observed correlation in the survey data, rather than a universal statement about high-rated employees.
E. The company's best-performing employees were motivated to perform well by the knowledge that they would receive performance ratings.
This assumption is not necessary for the personnel director's conclusion. The conclusion is about the satisfaction of the best-performing employees, not the specific motivation behind their performance. The survey data focus on the satisfaction of high-rated employees, but it does not explicitly link their motivation to their performance ratings.
Therefore, the correct assumption for the personnel director's conclusion is (B) The company's best-performing employees received high ratings.