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According to the Bureau of Labor Statistics, the official unemployment rate was \(10.4 \%\) among blacks and \(4.7 \%\) among whites as of February 2015\. (www.bls.gov/). a. Identify the response variable and the explanatory variable. b. Identify the two groups that are the categories of the explanatory variable. c. The unemployment statistics are based on a sample of individuals. Were the samples of white individuals and black individuals independent samples or dependent samples? Explain.

Short Answer

Expert verified
a. Response: unemployment rate; explanatory: race. b. Groups: blacks and whites. c. Independent samples; selection is separate.

Step by step solution

01

Understanding Variables

The response variable is the variable we are trying to understand or predict. In this case, we are interested in the unemployment rate, which varies depending on certain factors. The explanatory variable, on the other hand, is the variable that is used to explain changes in the response variable; here, it is the race of the individuals (black or white). Thus, the response variable is the unemployment rate, and the explanatory variable is race.
02

Identifying Groups of the Explanatory Variable

The explanatory variable in our scenario is race, which has been divided into two categories: blacks and whites. These categories are the two groups used to explain differences in the unemployment rate, our response variable.
03

Checking Sample Independence

For samples to be independent, the selection of individuals in one group should not affect the selection in another. Here, the samples of black and white individuals are independent because their selections are not linked. Each group's sample is drawn separately to determine their specific unemployment rates, making them independent of one another.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Explanatory Variables
In statistics, an explanatory variable is used to explore or predict changes in another variable, known as the response variable. In this exercise, the explanatory variable is the race of the individuals—either black or white. This categorization allows researchers to examine how different races might experience varying unemployment rates, which is our response variable in this scenario.

Understanding explanatory variables is crucial because these are the variables that drive the focus of the investigation. Researchers choose these variables based on their hypothesis or question, determining which variable they believe will affect the response variable. In our case, race is chosen because it may correlate with employment patterns.

Explanatory variables are sometimes also referred to as independent variables. However, it's important to note that in non-experimental studies, these variables are not manipulated by the researcher but simply observed to naturally occur differences.
Response Variables
The response variable, sometimes known as the dependent variable, is what researchers aim to explain or predict. In this exercise, the response variable is the unemployment rate, which is the outcome researchers are interested in examining.

By analyzing how different factors—here, racial differences—affect unemployment rates, researchers can uncover patterns or draw conclusions about economic inequalities. The response variable is typically measured and data collected on it can reveal important insights into the study's area of focus.

It is pivotal to ensure that the response variable is practically significant and measurable, as the conclusions and recommendations stemming from the research heavily rely on the response variable's variation.
Independent Samples
Independent samples are crucial in statistics when examining if the differences in traits or outcomes between groups are meaningful. In this exercise, the unemployment data is derived from independent samples of black and white individuals.

These samples are labeled independent because the selection process for black individuals does not influence the selection of white individuals’ sample and vice-versa. Each sample is collected independently to ensure that the results for each group are not intertwined by sample selection. This independence allows for a more unbiased comparison between groups.

Understanding independent samples helps clarify whether observed differences are indeed reflective of the true population differences or merely artifacts of the sampling method. Consequently, this independent sampling approach strengthens the reliability of the findings.

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