Frequencies simply count the number of persons who have a certain trait, attitude, opinion or behavior. Frequency distributions present the count and/or the percentage of persons who share that trait, attitude, opinion or behavior.
Sometimes, the most important information that we can find is how many, and what percentage, of a given group of people possess a given characteristic, have a particular opinion, engage in a particular activity, etc. For example, in studying customers and non-customers, frequencies might indicate the number of people in a survey who have purchased a product and those who have not purchased a product. Frequency distributions might indicate that 300 survey respondents have purchased a product (75%) and 100 have not purchased the product (25%). In a research report, frequency distributions are often reported for all relevant questions.