ASSIGNMENT 2B

A student at a local high school in Florida is interested in doing a research project about student diversity in the three public high schools in her county. She wants to investigate the proportion of public high school students in her county who self-identify as American Indian/Alaskan native, Asian, Black, Hispanic, White, or Multi-ethnic.

1) What is the population of interest? What should she consider if she wants to take a representative sample from this population?

The population of interest is public high school students in her county who identify as American Indian/Alaskan Native, Asian, Black, Hispanic, White, or multi-ethnic. She should consider having the representative sample be chosen randomly.

Whenever we take a sample from a population, there is the potential of introducing sampling bias. It is important to be aware of potential sources of bias and take steps to minimize the chance that sampling bias is present in the way that we sample.

Here are the four main sources of bias to consider when sampling from a population:

• Undercoverage occurs when some groups of the population are left out of the sampling process and the individuals in these groups do not have an equal chance of being selected for the sample. For example, a sample survey of households in a country may miss people who are homeless, prison inmates, or students living in dorms.

• Non-response bias occurs when an individual chosen for a sample cannot be contacted or decides to not participate in the study or research. This type of bias occurs after the sample has been selected and can create potential bias in the data collected.

• Response bias is defined as a systemic pattern of inaccurate responses to questions. This type of bias can occur when a person does not understand a question or feels influenced to respond to a question in a certain way. Response bias can also occur as a result of the wording of questions that are of a sensitive nature.

• A voluntary response bias is another form of bias because the sample is not random or representative of the population. The people who volunteer for a study or survey may be more inclined to respond to questions or report certain behaviors.

We need to be aware of the potential sources of bias that will prevent us from appropriately generalizing sample results to the population.

2) Let’s say the student takes a simple random sample of students from her high school and asks those students about their race/ethnicity. Describe any potential sources of bias in her sampling method.

Some potential source of bias could be people lying, location of the school, people who don’t know their ethnicity, and a specific ethnicity or race being randomly chosen more than others.

3) Assume the student creates a questionnaire that asks about race/ethnicity and then asks for volunteers at all three high schools to take the questionnaire. Describe any potential sources of bias in her sampling method.

Some potential sources of bias could be people who are not white answering or only white people answering. Voluntary response bias where there can be people more inclined to respond.

4) Since there are three public high schools in the student’s county, describe how she might select a representative sample. Explain how the method you chose minimizes bias.

She can select a representative sample by randomly selecting 35 students from each high school. This minimizes bias because you get an equal sample from each school.

5) This student wants to use the results of her study to describe the race/ethnicity of all high school-aged students in her county (ages 14–18). What is the population of interest now? Is the sample of students described in Question 4 appropriate for this population? Explain.

The population of interest is the race/ethnicity of all high school aged students in her county ages 14-18. This sample of students is not appropriate anymore for question 4 because it takes the whole county of high school kids rather than 3 public high schools.