Exercises 5–8 refer to the study of an association between which ear is used for cell phone calls and whether the subject is left-handed or right-handed. The study is reported in “Hemispheric Dominance and Cell Phone Use,” by Seidman et al., JAMA Otolaryngology— Head & Neck Surgery, Vol. 139, No. 5. The study began with a survey e-mailed to 5000 people belonging to an otology online group, and 717 surveys were returned. (Otology relates to the ear and hearing.)

Sampling Method What type of sampling best describes the way in which the 717 subjects were chosen: simple random sample, systematic sample, convenience sample, stratified sample, cluster sample? Does the method of sampling appear to adversely affect the quality of the results?

Study to check the association between two variables:

• The ear used for cell phone calls
• If the subjects are left or right-handed

The responses were collected through emails sent to an online group with 5000 people, out of which 717 responded.

As per the mode of sampling, an otology group was traced online to gather responses. The method is a type of convenience sampling.

In convenience sampling, the data is taken as per the mode that is easy to pursue.

In this study, a group was targeted straight away for responses.

Mostly, in convenience sampling, the results through the statistical analysis are expected to be inappropriate as the sample is not a clear population representative.

In the study, the two variables used do not differ much in value if the convenience sampling method is used from the true population values.

Thus, it can be regarded as a bias-free sample.