Customer satisfaction data is collected through surveys to ensure customers have positive experiences and will make future purchases. There are various methods to collect feedback, including phone calls, complaints, visits, and surveys. Common survey methods are face-to-face interviews, phone interviews, and mailed questionnaires, each with their own advantages and limitations. Proper sampling methods, like random sampling, are used to estimate satisfaction levels of large customer populations efficiently. Sample size depends on desired confidence level and margin of error. Results are often shown as the percentage of customers satisfied.