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Do girls think they don't need to take as many science classes as boys? The article "Intentions of Young Students to Enroll in Science Courses in the Future: An Examination of Gender Differences" (Science Education [1999]: 55-76) gives information from a survey of children in grades \(4,5,\) and \(6 .\) The 224 girls participating in the survey each indicated the number of science courses they intended to take in the future, and they also indicated the number of science courses they thought boys their age should take in the future. For each girl, the authors calculated the difference between the number of science classes she intends to take and the number she thinks boys should take. a. Explain why these data are paired. b. The mean of the differences was -.83 (indicating girls intended, on average, to take fewer classes than they thought boys should take), and the standard deviation was 1.51. Construct and interpret a \(95 \%\) confidence interval for the mean difference.

Short Answer

Expert verified
a) The data are paired because each data point consists of two measurements from the same individual. b) The 95% confidence interval for the mean difference is approximately \(-0.99, -0.67\) meaning that we are 95% confident that the true mean difference lies within this interval.

Step by step solution

01

Explaining why the data are paired

The data are paired as they come from the same individual. Each girl indicated both the number of science courses she intends to take and the number she thinks boys should take. Hence, there are two measures for each girl which are naturally paired.
02

Constructing the confidence interval

Firstly, recall that the confidence interval formula is given by \(\bar{x} \pm z \frac{s}{\sqrt{n}}\) where \(\bar{x}\) is the sample mean, \(z\) is the Z-value from the standard normal distribution corresponding to the desired confidence level, \(s\) is the standard deviation and \(n\) is the sample size. Given mean \(\bar{x} = -0.83\), standard deviation \(s = 1.51\) and \(n = 224\), and \(z = 1.96\) for a 95% confidence interval. Substituting the values, the confidence interval calculation will be: \(-0.83 \pm 1.96 \times \frac{1.51}{\sqrt{224}}\).
03

Calculating and interpreting the confidence interval

After plugging in the numbers and performing the calculation, you will get a confidence interval of around \(-0.99, -0.67\). This means that we're 95% confident that the true mean difference between the number of science courses each girl intends to take and the number she thinks boys should take lies between -0.99 and -0.67. It confirms that on average, girls think they should take fewer science courses than boys. We can use this confidence interval as an estimate of the population mean difference.

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Key Concepts

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

Science Course Enrollment Intentions
Understanding the intentions behind science course enrollment can provide valuable insights into the educational aspirations and perceptions among different student demographics. In the study referenced, a survey specifically targeted girls in grades 4 to 6 to determine any gender-based discrepancies in their science education plans. What became clear is that these intentions are shaped by a range of factors, such as societal expectations, personal interests, and perceived capabilities.

By shedding light on these intentions, educators can better tailor their approach to encourage greater inclusivity and interest in science education. It's crucial to support all students in recognizing the importance and accessibility of science, regardless of gender, and to inspire them to envision themselves in scientific roles in the future.
Paired Data Analysis
When dealing with paired data, the analysis revolves around two interrelated measurements taken from the same subject. In this scenario, each girl provided two types of information: the number of science courses she plans on taking, and the number she believes boys of their age should enroll in.

The pairing is intrinsic because the two measures come from identical respondents, making it reasonable to evaluate the differences within each pair. This analysis can reveal patterns or disparities in perceptions, such as gender-based expectations in educational intentions. Proper statistical methods must be used to handle such paired data to accurately draw conclusions about the studied group.
Confidence Interval Construction
Constructing a confidence interval is a statistical tool that allows us to estimate the range within which the true mean of a population is likely to fall, based on sample data. The formula used to calculate this interval involves the sample mean, the standard deviation, the Z-value associated with the desired confidence level, and the number of observations in the sample.

In constructing the confidence interval for the mean difference in the study, we start by identifying these components and applying them to the standard formula. The resulting interval gives us an understanding of where the actual mean likely sits within a defined level of confidence, in this case, 95%. It's a vital step for interpreting the data as it quantifies the certainty (or uncertainty) of our estimations.
Statistical Interpretation
Interpreting statistical outcomes, such as the confidence interval in this study, requires a careful consideration of what the numbers really imply about our population of interest. The confidence interval calculated suggests that there's a 95% likelihood that the true average difference in science courses girls intend to take versus what they think boys should take is between -0.99 and -0.67.

This tells us there's a statistically significant difference in enrollment intentions that favors boys. We interpret this as an indicator of a social or perceptual bias that could be influencing girls' decisions on science education. Understanding this interpretation enables educators and policymakers to make informed decisions aimed at addressing such disparities in educational settings.

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Most popular questions from this chapter

Public Agenda conducted a survey of 1379 parents and 1342 students in grades \(6-12\) regarding the importance of science and mathematics in the school curriculum (Associated Press, February \(15,2 \mathrm{OO} 6\) ). It was reported that \(50 \%\) of students thought that understanding science and having strong math skills are essential for them to succeed in life after school, whereas \(62 \%\) of the parents thought it was crucial for today's students to learn science and higher-level math. The two samples - parents and students -were selected independently of one another. Is there sufficient evidence to conclude that the proportion of parents who regard science and mathematics as crucial is different than the corresponding proportion for students in grades \(6-12 ?\) Test the relevant hypotheses using a significance level of .05 .

"Doctors Praise Device That Aids Ailing Hearts" (Associated Press, November 9,2004 ) is the headline of an article that describes the results of a study of the effectiveness of a fabric device that acts like a support stocking for a weak or damaged heart. In the study, 107 people who consented to treatment were assigned at random to either a standard treatment consisting of drugs or the experimental treatment that consisted of drugs plus surgery to install the stocking. After two years, \(38 \%\) of the 57 patients receiving the stocking had improved and \(27 \%\) of the patients receiving the standard treatment had improved. Do these data provide convincing evidence that the proportion of patients who improve is higher for the experimental treatment than for the standard treatment? Test the relevant hypotheses using a significance level of \(.05 .\)

Suppose that you were interested in investigating the effect of a drug that is to be used in the treatment of patients who have glaucoma in both eyes. A comparison between the mean reduction in eye pressure for this drug and for a standard treatment is desired. Both treatments are applied directly to the eye. a. Describe how you would go about collecting data for your investigation. b. Does your method result in paired data? c. Can you think of a reasonable method of collecting data that would not result in paired samples? Would such an experiment be as informative as a paired experiment? Comment.

The press release referenced in the previous exercise also included data from independent surveys of teenage drivers and parents of teenage drivers. In response to a question asking if they approved of laws banning the use of cell phones and texting while driving, \(74 \%\) of the teens surveyed and \(95 \%\) of the parents surveyed said they approved. The sample sizes were not given in the press release, but for purposes of this exercise, suppose that 600 teens and 400 parents of teens responded to the surveys and that it is reasonable to regard these samples as representative of the two populations. Do the data provide convincing evidence that the proportion of teens that approve of cell- phone and texting bans while driving is less than the proportion of parents of teens who approve? Test the relevant hypotheses using a significance level of .05

The article "Portable MP3 Player Ownership Reaches New High" (Ipsos Insight, June 29,2006 ) reported that in \(2006,20 \%\) of those in a random sample of 1112 Americans age 12 and older indicated that they owned an MP3 player. In a similar survey conducted in \(2005,\) only \(15 \%\) reported owning an \(\mathrm{MP} 3\) player. Suppose that the 2005 figure was also based on a random sample of size \(1112 .\) Estimate the difference in the proportion of Americans age 12 and older who owned an MP3 player in 2006 and the corresponding proportion for 2005 using a \(95 \%\) confidence interval. Is zero included in the interval? What does this tell you about the change in this proportion from 2005 to \(2006 ?\)

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