Answer:
The owner uses a database to print the names of all clients on slips of paper. The owner chooses 20 of the slips of paper without looking - YES
The owner sends a survey to every client who spent more than $500 with the catering company in the past year - NO
The owner sends a survey to all clients whose phone number ends in 5 - YES
The owner sends a survey to the last 20 clients who used the catering company's services - YES
Step-by-step explanation:
Random sampling is one of the sampling techniques commonly used in which each sample in the given population has an equal chance,likelihood or probability of being selected. This will further imply that random sample from a population should be unbiased or free from sampling bias.
Sampling bias refers to a bias in sampling in which sample observations are collected in such a way that some participants of the intended population have a high likelihood of being included than others.
In the first scenario, the owner uses a database to print the names of all clients on slips of paper. The owner chooses 20 of the slips of paper without looking. This method will result in a random sample of the population as we are told the owner chooses 20 of the slips of paper without looking hence the sample will be free from bias.
In the second scenario, the owner sends a survey to every client who spent more than $500 with the catering company in the past year. This method will not result in a random sample of the population since the sample will only focus on a particular class of individuals hence prone to sampling bias.
In the third scenario, the owner sends a survey to all clients whose phone number ends in 5. This method will result in a random sample of the population because the phone numbers are themselves random in nature hence free from sampling bias.
The owner sends a survey to the last 20 clients who used the catering company's services. This method will result in a random sample of the population since the last 20 clients did not follow any particular pattern hence random.