Final answer:
The HR department relies on the number of applicants to determine the success of a recruiting advertisement.
Step-by-step explanation:
The HR department relies on the Number of applicants to determine how successful a recruiting advertisement was in finding qualified applicants. By tracking the number of applicants who respond to a job posting, the HR department can measure the level of interest the advertisement generated and assess the effectiveness of the recruiting efforts. For example, if a job posting receives a high number of qualified applicants, it suggests that the advertisement reached a suitable audience and resonated with potential candidates.