Each of the following is a source of error in a sample survey. Label each as sampling error or non sampling error, and explain your answers.

(a) The telephone directory is used as a sampling frame.

(b) The person cannot be contacted in five calls.

(c) Interviewers choose people walking by on the sidewalk to interview.

2. A survey paid for by makers of disposable diapers found that $84\%$ of the sample opposed banning disposable diapers. Here is the actual question:

As a sampling frame, the telephone directory is used. In five attempts, the person cannot be reached. Interviews are conducted with folks who are passing by on the sidewalk.

The inaccuracy created by observing a sample rather than the entire population is known as sampling error.

Any disparity between a statistic and its related parameter is referred to as sampling error. To put it another way, it's a statistical error that arises when the sample doesn't represent the full population. A sampling frame is chosen from the telephone directory. Because it is tied to how the sample is chosen, this is an example of a sampling mistake.

In five attempts, the person cannot be reached:

This is an example of a non-sampling error because it involves data gathering and has nothing to do with the survey design. It has nothing to do with the survey's design and is related to data gathering.

Interviews are conducted with persons who are passing by on the sidewalk:

Because it is tied to how the sample is conducted, this is an example of sampling error. The sample is made up of people on the street, not a select handful. The sample is made up of ordinary people, not a select few.