Chapter 3.2 – Collect and Analyse Data Sometimes a person collects data by directly asking people their opinions or by personally conducting an experiment or survey. Sometimes a person collects data by directly asking people their opinions or by personally conducting an experiment or survey.

On the other hand, sometimes a person collects data by researching work that others have already done, whether through books or on the internet. On the other hand, sometimes a person collects data by researching work that others have already done, whether through books or on the internet.

These two opposites represent the difference between getting information from a primary source or getting information from a secondary source. These two opposites represent the difference between getting information from a primary source or getting information from a secondary source.

A primary source is a person who collects data for their own use. When you conduct a survey or perform an experiment, you are the primary source of the data A primary source is a person who collects data for their own use. When you conduct a survey or perform an experiment, you are the primary source of the data

A secondary source is a database, or research collected by someone else. When you work with data from the Internet or from published materials, you are using a secondary source. A secondary source is a database, or research collected by someone else. When you work with data from the Internet or from published materials, you are using a secondary source.

Bias Recall that a survey contains bias if it does not reflect the population

We talk about three types of bias in this course: 1.Response Bias 2.Measurement Bias 3.Non-Response Bias

1.Response Bias  Response bias can affect the results of a survey if people answer questions in the way they think the questioner wants them to answer …

 … rather than according to their true beliefs

 Examples of response bias include leading questions and loaded questions.

A leading question is a question which suggests the “correct” answer due to the way it is asked.

Example of a Leading Question Don’t you think that Eddie Francis should be re-elected as mayor of Windsor?

A loaded question also suggests the correct answer, but it does so by providing information within the question. A loaded question also suggests the correct answer, but it does so by providing information within the question.

Example of a Loaded Question Eddie Francis has helped create new jobs in the city of Windsor. Do you think he should be re-elected as mayor of Windsor? Eddie Francis has helped create new jobs in the city of Windsor. Do you think he should be re-elected as mayor of Windsor?

2.Measurement Bias Measurement bias refers to survey questions that restrict certain answers from being given, even though they don’t necessarily suggest the one right answer.

A common example is a multiple choice question about a matter of opinion.

Example of Measurement Bias Who do you think is the best female tennis player of all time?

a) Martina Navratilova b) Chris Evert c) Billie Jean King d) Serena Williams e) Other:____________

Although this question does not necessarily suggest the one right answer, it could restrict someone from naming a player not on the list.

3. Non-Response Bias Non-response bias is not the opposite of response bias.

Rather, non-response bias occurs if the people who choose not to respond differ from those who respond in some important characteristic.

Example of Non-Response Bias A restaurant manager decides to ask customers to fill out a survey dealing with food quality. Thirty percent of the customers respond.

Of those that respond, many complain about poor food quality.

This could be a case of non-response bias, because many of the people who were satisfied with the food don’t feel the need to respond, …

… whereas people who were upset with the food want to vent their frustration.