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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 is paired because each girl gives two pieces of information which inherently correspond to each other. b) After calculating the standard error, the 95% confidence interval for the mean difference can be calculated using the given mean and a z-score of 1.96. This interval is the range that we are 95% confident contains the true mean difference in the number of science classes girls intend to take versus the number they think boys should take.

Step by step solution

01

Understanding Paired Data

Each girl participating in the survey gave two pieces of information: the number of science courses she plans to take and the number of science courses she thought boys should take. These two responses are naturally paired because they come from the same individual, and hence, relate to each other directly. This is why the data are considered paired.
02

Calculating Standard Error

We are given the standard deviation and the total number of data points (girls) which is 224. We can calculate the standard error by dividing the standard deviation by the square root of the total number of data points. The formula for calculating standard error is \(\sigma/\sqrt{n}\), where \(\sigma\) is the standard deviation and \(n\) is the total number of data points. Plugging in the given values, the standard error = \(\frac{1.51}{\sqrt{224}}\).
03

Computing 95% Confidence Interval

Now we are using z-score for 95% confidence interval, which is approximately 1.96. The formula for the confidence interval is \(\bar{x} \pm z \times \text{Standard Error}\). Substituting the values, we get confidence interval = \(-0.83 \pm 1.96 \times \text{Standard Error}\). This will give a range that we are 95% confident contains the true mean difference.

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Key Concepts

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

Confidence Interval
A confidence interval provides an estimated range of values which is likely to include an unknown population parameter. In this context, we focus on determining a 95% confidence interval for the mean difference in the number of science classes intended by girls versus what they think boys should take.
To find this interval, we use the mean difference and standard error calculated from the sample data. In this problem, the given mean difference is \-0.83\, which shows that on average, girls intend to take fewer science classes than they believe boys should. The formula to calculate the confidence interval is:
  • \( \bar{x} \pm z \times \text{Standard Error} \)
  • where \( \bar{x} \) is the sample mean, z is the z-score corresponding to the desired confidence level (1.96 for 95%), and \text{Standard Error} is the standard error calculated from the data.
The computed interval provides a range that, with 95% probability, encapsulates the true mean difference in intentions.
Paired Data
In this study, each girl was asked two related questions: how many science classes she intends to take and how many she thinks boys should take. Since both answers come from the same participant, the data are naturally paired. This kind of data pairing often occurs in studies comparing two related measurements. Paired data are advantageous in statistical studies because they can control for individual variability. For example, when each participant provides two responses, differences between their perceptions of themselves and boys are more accurately assessed. By looking at the differences within paired data sets, researchers can eliminate variability that might affect unpaired data, which in turn can lead to more precise results. In this case, understanding that the data are paired is crucial as it determines the appropriate statistical analysis to use, ensuring more reliable conclusions.
Gender Differences in Education
Gender differences in education, particularly in STEM (Science, Technology, Engineering, and Mathematics) fields, have long been a subject of interest and research. In this exercise, the focus is on the differing intentions of boys and girls regarding science courses, as highlighted by the survey among young students. The survey results showed that, on average, girls intended to take fewer science courses than they thought boys should. This finding reflects perceived educational gender norms at that age and might relate to wider societal expectations or stereotypes about gender roles in science.
Understanding these gender differences can be instrumental in creating educational policies and interventions aimed at promoting gender equality, encouraging more girls to pursue science subjects, and breaking down barriers associated with traditional gender roles in education.
Sample Standard Deviation
Sample standard deviation is a statistical measure that provides insight into the variability or spread of a data set. In this scenario, the provided standard deviation is 1.51, which indicates how much the differences in intended science courses between girls and boys vary from the average. The sample standard deviation is crucial for constructing confidence intervals, as it helps calculate the standard error when determining how accurately the sample mean represents the population mean. It helps to understand the distribution of data; a larger standard deviation suggests more widespread differences in responses, while a smaller one indicates responses are more tightly clustered around the mean. Calculating standard deviation involves determining the square root of the average of squared deviations from the mean. It provides researchers with a necessary measure of spread to conduct further statistical analysis effectively, aiding in more precise and informed educational research.

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Most popular questions from this chapter

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