Question

A statistics student who is curious about the relationship between the amount of time students spend on social networking sites and their performance at school decides to conduct a survey. Three research strategies for collecting data are described below. Match each strategy with the correct sampling method. He randomly samples 40 students from the study's population, gives them the survey, asks them to fill it out and bring it back the next day. Answer 1 He gives out the survey only to his friends, and makes sure each one of them fills out the survey. Answer 2 He posts a link to an online survey on his Facebook wall and asks his friends to fill out the survey. Answer 3

Answer 1

solution:

strategy 1:

He randomly samples 40 students from the study's population, gives them the survey, asks them to fill it out and bring it back the next day.

• it is an example of simple random sampling. the only bias expected with this sampling method is non response bias .the non response bias occurs when some people whom you sampled refused to participate in the sampling because the questionnaire might contain question which needs personal information illegal activity embarrassing information.

strategy 2:

He gives out the survey only to his friends, and makes sure each one of them fills out the survey.

• the student only gives questionnaire to his friends it is an example of convenience sampling a convenience sampling is a non probability sampling in which a sample is drawn from a part of population which is convenient or easily accessible to the researcher.this strategy expected to have a self selection bias .a self selection bias is a subcategory of selection bias it does not represent the whole population opinion in a correct manner.

strategy 3:

He posts a link to an online survey on his Facebook wall and asks his friends to fill out the survey.

• it is an example of convenience sampling and it is expected that this strategy may have the under coverage bias because only those persons will be in the sample who are on face book and are friend with him