Chain referral sampling is also known as snowball sampling. In this form of sampling, the samples are collected from the referrals given by the existing samples. The samples are collected and the research is conducted respectively. This method is used in the business marketing also. The places where the people are not known by the company, the method of chain referrals are made and the samples are collected.
The density (d) is the number of units(n) per volume (V): d = n/V We know: d = 0.3 fish/ft³. V = 30 ft³ n = ? d = n/V n = d * V n = 0.3 fish/ft³ * 30 ft³ n = 9 fish
