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For each of the following situations, state whether the parameter of interest is a mean or a proportion. It may be helpful to examine whether individual responses are numerical or categorical. (a) In a survey, one hundred college students are asked how many hours per week they spend on the Internet. (b) In a survey, one hundred college students are asked: "What percentage of the time you spend on the Internet is part of your course work?" (c) In a survey, one hundred college students are asked whether or not they cited information from Wikipedia in their papers. (d) In a survey, one hundred college students are asked what percentage of their total weekly spending is on alcoholic beverages. (e) In a sample of one hundred recent college graduates, it is found that 85 percent expect to get a job within one year of their graduation date.

Short Answer

Expert verified
(a) Mean, (b) Mean, (c) Proportion, (d) Mean, (e) Proportion.

Step by step solution

01

Understand the Data Type

First, identify whether the responses in each survey situation involve numerical or categorical data.
02

Analyze Situation (a)

In this case, students are asked how many hours they spend on the Internet. Since 'hours' is numerical, the parameter of interest is the mean.
03

Analyze Situation (b)

Students are asked about the percentage of time on the Internet related to coursework. 'Percentage' is numerical, so the parameter of interest is the mean.
04

Analyze Situation (c)

Students are asked whether they cited Wikipedia, which yields a yes or no response. This is categorical data, hence the parameter of interest is a proportion.
05

Analyze Situation (d)

Students are asked for a percentage of spending on alcohol, which is a numerical response, making the parameter of interest a mean.
06

Analyze Situation (e)

The survey result gives 85 percent expecting a job within a year, indicating categorical data of success/failure. Here, the parameter of interest is a proportion.

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Key Concepts

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

Understanding Numerical Data
Numerical data refers to information that is measured or counted and can be represented as numbers. In surveys, when questions involve responses that can be quantified, such as hours or percentages, the data is numerical. For instance, if students are asked how many hours they spend online, that response is a clear, measurable value. Such data allows for calculations like mean, median, or standard deviation.

Numerical data is fundamental in descriptive statistics because it helps determine central tendencies like the mean or average, giving an idea of a typical value within a data set. When working with numerical data, statisticians can apply various mathematical and statistical operations to explore the data deeper.
Exploring Categorical Data
Categorical data includes responses that are categorized into distinct groups or categories. Instead of numerical values, categorical data represents characteristics or qualities, such as gender, colors, or preferences like 'yes' or 'no.' In survey examples, when students respond with 'yes' or 'no' questions, like citing Wikipedia, their responses are categorical.

Analyzing categorical data helps in understanding proportions or the frequency of responses within each category. Rather than calculating a mean, statisticians often look at proportions or percentages to understand how data divides among various categories. It involves counting and comparing the number of observations within each category to draw meaningful conclusions.
Defining Statistical Parameter
A statistical parameter is a measurable characteristic of a population, such as a mean or a proportion. It provides insights into overall trends and behaviors within a data set. Parameters are crucial in statistical analyses as they help summarize and communicate key data insights effectively.

In contexts involving numerical data, the mean is often used as a parameter to indicate an average value. For categorical data, the proportion (i.e., the percentage of a category existing within the data) is more relevant. Parameters are essential for summarizing a data set comprehensively, helping to make predictions or test statistical hypotheses.
Analyzing Surveys Effectively
Survey analysis involves collecting, processing, and interpreting data obtained from surveys to uncover insights about specific questions or topics. Surveys are powerful tools for gathering both numerical and categorical data. They provide a snapshot of opinions, behaviors, or characteristics of a group at a point in time.

Effective survey analysis begins by identifying the data type—numerical or categorical—and then determining the appropriate statistical methods to apply. Finally, analyzing survey data helps in understanding trends, making data-driven decisions, and fostering a deeper understanding of the subject matter. A good survey analysis systematically interprets both numerical means and categorical proportions to paint a clear picture of the data.

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Most popular questions from this chapter

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In 2013, the Pew Research Foundation reported that "45\% of U.S. adults report that they live with one or more chronic conditions". \({ }^{11}\) However, this value was based on a sample, so it may not be a perfect estimate for the population parameter of interest on its own. The study reported a standard error of about \(1.2 \%\), and a normal model may reasonably be used in this setting. Create a \(95 \%\) confidence interval for the proportion of U.S. adults who live with one or more chronic conditions. Also interpret the confidence interval in the context of the study.

A nonprofit wants to understand the fraction of households that have elevated levels of lead in their drinking water. They expect at least \(5 \%\) of homes will have elevated levels of lead, but not more than about \(30 \%\). They randomly sample 800 homes and work with the owners to retrieve water samples, and they compute the fraction of these homes with elevated lead levels. They repeat this 1,000 times and build a distribution of sample proportions. (a) What is this distribution called? (b) Would you expect the shape of this distribution to be symmetric, right skewed, or left skewed? Explain your reasoning. (c) If the proportions are distributed around \(8 \%,\) what is the variability of the distribution? (d) What is the formal name of the value you computed in (c)? (e) Suppose the researchers' budget is reduced, and they are only able to collect 250 observations per sample, but they can still collect 1,000 samples. They build a new distribution of sample proportions. How will the variability of this new distribution compare to the variability of the distribution when each sample contained 800 observations?

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