/*! 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 63 In each of Exercises 61 to 64, s... [FREE SOLUTION] | 91影视

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In each of Exercises 61 to 64, say which inference procedure from Chapter 8, 9, or 10 you would use. Be specific. For example, you might say, 鈥淭wo-sample z test for the difference between two proportions.鈥 You do not need to carry out any procedures. Looking back on love How do young adults look back on adolescent romance? Investigators interviewed 40 couples in their midtwenties. The female and male partners were interviewed separately. Each was asked about his or her current relationship and also about a romantic relationship that lasted at least two months when they were aged 15 or 16. One response variable was a measure on a numerical scale of how much the attractiveness of the adolescent partner mattered. You want to compare the men and women on this measure.

Short Answer

Expert verified
Use a two-sample t-test to compare the means for men and women.

Step by step solution

01

Identify the Purpose of the Study

The exercise aims to compare how much the attractiveness of an adolescent partner mattered to men and women based on responses obtained from interviews. Hence, the objective is to compare two distinct groups on a numerical scale.
02

Determine the Type of Data

The data involves a numerical scale that assesses how much the attractiveness of an adolescent partner mattered, with separate scores for male and female partners.
03

Identify the Comparison Groups

The comparison is between two independent groups: males and females. Each group provides data concerning the same kind of measure.
04

Choose the Appropriate Inference Procedure

Given that the comparison involves two independent groups with a numerical outcome, the appropriate inference procedure will be the two-sample t-test. This test is used to determine if there is a significant difference between the means of two independent groups.

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Key Concepts

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

Two-sample t-test
A two-sample t-test is a statistical method used to determine if there is a significant difference between the means of two separate groups. These groups must have independent observations, meaning the sample in one group does not influence or overlap with the sample in the other. In the context of the exercise, we use a two-sample t-test to compare the importance men and women place on the attractiveness of their adolescent partners.
This test is well-suited for data that is approximately normally distributed, and where each group has a similar variance. Key aspects of the two-sample t-test include:
  • Checking assumptions of normality for the data sets.
  • Calculating the mean and variability for each group.
  • Assessing whether the observed mean difference is statistically significant.
By understanding these components, you can effectively utilize the two-sample t-test to draw informed conclusions about your data.
Independent Groups
In statistics, independent groups refer to groups where the observations in one do not affect those in the other. This independence is crucial, especially when conducting a two-sample t-test, as mixing data or influencing results could lead to biased outcomes.
In the given exercise, men and women represent these independent groups, as their scores on the importance of physical attractiveness are obtained separately without influencing one another. Characteristics of independent groups include:
  • No overlap in participants between groups.
  • Each group's observations are collected under similar conditions.
  • The performance of one group does not impact the other.
Maintaining these conditions helps ensure the validity of the statistical conclusions drawn from testing.
Numerical Scale
A numerical scale provides a quantitative measure that allows for comparison between different entities. In the context of the exercise, researchers are using a numerical scale to quantify the importance that young adults assign to the attractiveness of their adolescent partners. Numerical scales can involve:
  • Discrete or continuous measurements depending on the nature of data.
  • Intervals that hold meaning, allowing for a variety of statistical analyses.
  • Data that can be ordinal, but ideally ratio or interval for most robust comparisons.
This kind of quantification is essential for performing meaningful data analysis, like the two-sample t-test, to compare numerical data between groups.
Data Analysis
Data analysis is the process of systematically applying statistical methods to evaluate and interpret data, aiming to derive meaningful insights. The action of comparing responses across the independent groups, like in this exercise, forms an integral part of data analysis.
By performing a two-sample t-test, you engage in a core step of data analysis: testing hypotheses regarding differences between group means. Effective data analysis involves:
  • Cleaning and preparing data to ensure accuracy.
  • Selecting appropriate statistical tests based on data characteristics.
  • Interpreting results in the context of the research question.
This analytical process helps in understanding trends, patterns, and making evidence-based conclusions, providing significant value to research efforts.

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Most popular questions from this chapter

Paired or unpaired? In each of the following settings, decide whether you should use paired \(t\) procedures or two-sample t procedures to perform inference. Explain your choice.\(^{43}\) (a) To compare the average weight gain of pigs fed two different rations, nine pairs of pigs were used. The pigs in each pair were littermates. A coin toss was used to decide which pig in each pair got Ration A and which got Ration B. (b) A random sample of college professors is taken. We wish to compare the average salaries of male and female teachers. (c) To test the effects of a new fertilizer, 100 plots are treated with the new fertilizer, and 100 plots are treated with another fertilizer. A computer鈥檚 random number generator is used to determine which plots get which fertilizer.

Information online \((8.2,10.1)\) A random digit dialing sample of 2092 adults found that 1318 used the Internet. \(^{45}\) Of the users, 1041 said that they expect businesses to have Web sites that give product information; 294 of the 774 nonusers said this. (a) Construct and interpret a 95% confidence interval for the proportion of all adults who use the Internet. (b) Construct and interpret a 95% confidence interval to compare the proportions of users and nonusers who expect businesses to have Web sites.

Paired or unpaired? In each of the following settings, decide whether you should use paired \(t\) procedures or two-sample t procedures to perform inference. Explain your choice.\(^{42}\) (a) To test the wear characteristics of two tire brands, A and B, each brand of tire is randomly assigned to 50 cars of the same make and model. (b) To test the effect of background music on productivity, factory workers are observed. For one month, each subject works without music. For another month, the subject works while listening to music on an MP3 player. The month in which each subject listens to music is determined by a coin toss. (c) A study was designed to compare the effectiveness of two weight-reducing diets. Fifty obese women who volunteered to participate were randomly assigned into two equal-sized groups. One group used Diet A and the other used Diet B. The weight of each woman was measured before the assigned diet and again after 10 weeks on the diet.

Exercises 71 to 74 refer to the following setting. Coaching companies claim that their courses can raise the SAT scores of high school students. Of course, students who retake the SAT without paying for coaching generally raise their scores. A random sample of students who took the SAT twice found 427 who were coached and 2733 who were uncoached.\(^{44}\) Starting with their Verbal scores on the first and second tries, we have these summary statistics: Coaching and SAT scores (10.1) What proportion of students who take the SAT twice are coached? To answer this question, Jannie decides to construct a 99% confidence interval. Her work is shown below. Explain what鈥檚 wrong with Jannie鈥檚 method. $$hat{p}_{1}=\frac{427}{3160}=0.135=\underset{\text { who were coached }}{\text { proportion of students }}$$ $$\hat{p}_{2}=\frac{2733}{3160}=0.865=\underset{\text { who weren't coached }}{\text { who weren't coached }}$$ $$\mathrm{A} 99 \% \mathrm{Cl} \text { for } p_{1}-p_{2} \mathrm{is}$$ $$\begin{aligned}(0.135-0.865) \pm 2.575 \sqrt{\frac{0.135(0.865)}{3160}} &+\frac{0.865(0.135)}{2733} \\ &=-0.73 \pm 0.022=(-0.752,-0.708) \end{aligned}$$ We are 99% confident that the proportion of students taking the SAT twice who are coached is between 71 and 75 percentage points lower than students who aren鈥檛 coached.

What鈥檚 wrong? A driving school wants to find out which of its two instructors is more effective at preparing students to pass the state鈥檚 driver鈥檚 license exam. An incoming class of 100 students is randomly assigned to two groups, each of size 50. One group is taught by Instructor A; the other is taught by Instructor B. At the end of the course, 30 of Instructor A鈥檚 students and 22 of Instructor B鈥檚 students pass the state exam. Do these results give convincing evidence that Instructor A is more effective? Min Jae carried out the significance test shown below to answer this question. Unfortunately, he made some mistakes along the way. Identify as many mistakes as you can, and tell how to correct each one. State: I want to perform a test of $$H_{0} : p_{1}-p_{2}=0$$ $$H_{a} : p_{1}-p_{2}>0$$ where \(p_{1}=\) the proportion of Instructor A's students that passed the state exam and \(p_{2}=\) the proportion of Instructor B's students that passed the state exam. Since no significance level was stated, I'll use \(\sigma=0.05\) Plan: If conditions are met, I'll do a two-sample \(z\) test for comparing two proportions. \(\bullet\) Random The data came from two random samples of 50 students. \(\bullet\) Normal The counts of successes and failures in the two groups - \(30,20,22\) , and \(28-\) are all at least \(10 .\) \(\bullet\) Independent There are at least 1000 students who take this driving school's class. Do: From the data, \(\hat{p}_{1}=\frac{20}{50}=0.40\) and \(\hat{p}_{2}=\frac{30}{50}=0.60 .\) So the pooled proportion of successes is $$\hat{p}_{C}=\frac{22+30}{50+50}=0.52$$ \(\bullet\) Test statistic $$z=\frac{(0.40-0.60)-0}{\sqrt{\frac{0.52(0.48)}{100}+\frac{0.52(0.48)}{100}}}=-2.83$$ Conclude: The P-value, \(0.9977,\) is greater than \(\alpha=\) \(0.05,\) so we fail to reject the null hypothesis. There is not convincing evidence that Instructor A's pass rate is higher than Instructor B's.

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