Quantitative research, in contrast to qualitative research, refers to numerical and data-based research. The basic methods used to investigate numerical data are called ‘statistics’. In order for the results to be meaningful, the design of the questionnaires, sample size, scope, and measurement method should be determined the right way. The calculation module here can be used for a statistically significant sample size. When conducting research, 95% confidence interval and 5% margin of error are generally used. For example, while an experience measurement is made for 1 million calls to the call center, 385 successful surveys are needed according to these values. Confidence interval and margin of error become better as the sample increases, but after a point, increasing the sample size is not very effective. Surveys such as Net Promoter Score surveys, and Customer satisfaction (See Customer Satisfaction Score) surveys are quantitative research.