/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 37 One True Love? Data 2.1 on page ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

One True Love? Data 2.1 on page 46 deals with a survey that asked whether people agree or disagree with the statement "There is only one true love for each person." The survey results in Table 2.1 show that 735 of the 2625 respondents agreed, 1812 disagreed, and 78 answered "don't know." (a) Find a \(90 \%\) confidence interval for the proportion of people who disagree with the statement. (b) Find a \(90 \%\) confidence interval for the proportion of people who "don't know." (c) Which estimate has the larger margin of error?

Short Answer

Expert verified
The 90% confidence interval for the proportion of people who disagree with the statement is approximately (0.664, 0.716) and for those who 'don't know' the interval is approximately (0.022, 0.037). The disagreement estimate has a larger margin of error.

Step by step solution

01

Calculate Proportions

Calculate the proportion of people who disagree with the statement and those who 'don't know.' The proportion is calculated as the number of respondents for each category divided by the total number of respondents. For the respondents who disagree: \(P_{disagree} = \frac{1812}{2625} = 0.6901\). For the respondents who 'don't know': \(P_{dk} = \frac{78}{2625} = 0.0297\)
02

Calculate Confidence Intervals

The formula to calculate a 90% confidence interval is \(\hat{p} \pm Z * \sqrt{\frac{\hat{p}*(1-\hat{p})}{n}}\) where \(\hat{p}\) is the proportion, \(Z\) is the z-score which will be 1.645 for a 90% confidence interval and \(n\) is the total number of responses. The confidence interval for those who disagree is \(0.6901 \pm 1.645*\sqrt{\frac{0.6901*(1-0.6901)}{2625}}\) which is approximately (0.664, 0.716). For the 'don't know' responses, the confidence interval is \(0.0297 \pm 1.645*\sqrt{\frac{0.0297*(1-0.0297)}{2625}}\) which is around (0.022, 0.037).
03

Compare Margins of Error

The margin of error for each estimate can be calculated as the range of the 90% confidence interval divided by 2. For those who disagreed, the margin of error is \(\frac{0.716-0.664}{2} = 0.026\). For those who 'don't know', the margin of error is approximately \(\frac{0.037-0.022}{2} = 0.0075\). So the estimate for those who disagreed has a larger margin of error.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

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

Survey Data Analysis
Analyzing survey data is an essential process in research as it helps to understand the opinions or behaviors of a population based on sampled responses. When dealing with survey data, it's crucial to accurately measure the sentiments of respondents. For example, in the exercise given, the survey asks about beliefs regarding 'one true love.' To analyze the data, one must look at the proportion of responses in each category (agree, disagree, don't know). It is by examining these proportions that researchers can gain insights into the prevailing opinions among the respondents.

However, survey data analysis doesn't stop at simple proportion calculations. To make these proportions meaningful, researchers often calculate confidence intervals to understand the precision of the estimates within the context of the population. This signifies how reliable our estimates are and helps to infer the range within which the true sentiment of the overall population lies. In other words, it gives us boundaries within which we are 'confident' that the true proportion exists.
Margin of Error
The margin of error is a statistic expressing the amount of random sampling error in a survey's results. It represents the range either side of an estimated value within which the true value is likely to fall with a stated level of confidence. The smaller the margin of error, the closer we are to having exact answers.

To illustrate this concept, let's look at a practical example from the exercise. When calculating the confidence intervals for both the respondents who disagreed and those who said 'don't know', the margin of error is an essential part of the calculation. It is the half-width of the confidence interval and directly influences how we interpret the precision of our estimates. In the example, the 'disagree' responses had a larger margin of error, indicating that this estimate is less precise than the 'don't know' estimates, which had a smaller margin of error. This is important when presenting survey results as it frames the reliability of the figures presented.

Understanding Margin of Error

It's useful to note that the margin of error can be affected by several factors, including sample size, the level of confidence chosen, and the variability within the sample. As seen in the exercise, a larger margin means a wider confidence interval, suggesting greater uncertainty about the exact proportion of the population that holds a particular opinion. When interpreting survey results, one should always consider the margin of error alongside the reported proportion.
Proportion Calculation
At the heart of analyzing survey results is the task of calculating proportions. A proportion represents a part or fraction of a whole, typically expressed as a percentage. It's a way to describe how large one group is in relation to the overall sample or population.

As demonstrated in the exercise, to find the proportion of respondents who disagree or don't know in the survey, each category must be divided by the total number of responses. This simple calculation provides a quick snapshot of where the majority opinion lies or how significant a minority viewpoint is. In research, these proportion calculations are the first step in making sense of the collected data. They provide the foundational figures that lead to further statistical analysis, such as the confidence intervals discussed.

Significance of Proportion Calculation

Calculating the proportion is more than just arithmetic; it's about understanding the distribution of opinions or behaviors within your data set. By doing this, researchers can identify patterns, trends, or outliers. For instance, in the survey about 'one true love', knowing the proportions of disagreement and uncertainty contributes to a broader discussion on perspectives about love and relationships across the sampled population. Accurate proportion calculations are therefore essential for insightful data analysis and informed decision-making.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Use StatKey or other technology to generate a bootstrap distribution of sample means and find the standard error for that distribution. Compare the result to the standard error given by the Central Limit Theorem, using the sample standard deviation as an estimate of the population standard deviation. Mean commute time in Atlanta, in minutes, using the data in CommuteAtlanta with \(n=500\), \(\bar{x}=29.11,\) and \(s=20.72\)

In each case below, two sets of data are given for a two-tail difference in means test. In each case, which version gives a smaller \(\mathrm{p}\) -value relative to the other? (a) Both options have the same standard deviations and same sample sizes but: \(\begin{array}{lll}\text { Option 1 has: } & \bar{x}_{1}=25 & \bar{x}_{2}=23\end{array}\) Option 2 has: \(\quad \bar{x}_{1}=25 \quad \bar{x}_{2}=11\) (b) Both options have the same means \(\left(\bar{x}_{1}=22,\right.\) \(\left.\bar{x}_{2}=17\right)\) and same sample sizes but: Option 1 has: \(\quad s_{1}=15 \quad s_{2}=14\) $$ \text { Option 2 has: } \quad s_{1}=3 \quad s_{2}=4 $$ (c) Both options have the same means \(\left(\bar{x}_{1}=22,\right.\) \(\bar{x}_{2}=17\) ) and same standard deviations but: Option 1 has: \(\quad n_{1}=800 \quad n_{2}=1000\) Option 2 has: \(\quad n_{1}=25 \quad n_{2}=30\)

If random samples of the given sizes are drawn from populations with the given proportions: (a) Find the mean and standard error of the distribution of differences in sample proportions, \(\hat{p}_{A}-\hat{p}_{B}\) (b) If the sample sizes are large enough for the Central Limit Theorem to apply, draw a curve showing the shape of the sampling distribution. Include at least three values on the horizontal axis. Samples of size 40 from population \(A\) with proportion 0.30 and samples of size 30 from population \(B\) with proportion 0.24

We saw in Exercise 6.260 on page 425 that drinking tea appears to offer a strong boost to the immune system. In a study extending the results of the study described in that exercise, \(^{70}\) blood samples were taken on five participants before and after one week of drinking about five cups of tea a day (the participants did not drink tea before the study started). The before and after blood samples were exposed to e.coli bacteria, and production of interferon gamma, a molecule that fights bacteria, viruses, and tumors, was measured. Mean production went from 155 \(\mathrm{pg} / \mathrm{mL}\) before tea drinking to \(448 \mathrm{pg} / \mathrm{mL}\) after tea drinking. The mean difference for the five subjects is \(293 \mathrm{pg} / \mathrm{mL}\) with a standard deviation in the differences of 242 . The paper implies that the use of the t-distribution is appropriate. (a) Why is it appropriate to use paired data in this analysis? (b) Find and interpret a \(90 \%\) confidence interval for the mean increase in production of interferon gamma after drinking tea for one week.

Random samples of the given sizes are drawn from populations with the given means and standard deviations. For each scenario: (a) Find the mean and standard error of the distribution of differences in sample means, \(\bar{x}_{1}-\bar{x}_{2}\) (b) If the sample sizes are large enough for the Central Limit Theorem to apply, draw a curve showing the shape of the sampling distribution. Include at least three values on the horizontal axis. Samples of size 300 from Population 1 with mean 75 and standard deviation 18 and samples of size 500 from Population 2 with mean 83 and standard deviation 22

See all solutions

Recommended explanations on Math Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.