Insurers predict the chance of loss primarily through thelaw of large numbers, a fundamental principle taught in Pennsylvania Life, Accident, and Health Insurance study guides. This law states that as the number of exposure units increases, the actual loss experience will more closely match the expected loss experience. By insuring a large group of similar risks, insurers can more accurately forecast losses and set appropriate premium rates.

Average disability occurrences and census tables are tools derived from this principle but do not explainhowpredictions are made. Insurable interest is a legal requirement ensuring the policyowner has a legitimate financial interest in the insured but has no role in loss prediction. The law of large numbers allows insurers to rely on statistical probability rather than guesswork, forming the foundation of underwriting, rate development, and financial stability. Consequently, option B is the correct and verified answer.