/*! 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 23 Exercises 23 through 25 refer to... [FREE SOLUTION] | 91Ó°ÊÓ

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Exercises 23 through 25 refer to the following setting. Do students who read more books for pleasure tend to earn higher grades in English? The boxplots below show data from a simple random sample of 79 students at a large high school. Students were classified as light readers if they read fewer than 3 books for pleasure per year. Otherwise, they were classified as heavy readers. Each student's average English grade for the previous two marking periods was converted to a GPA scale where \(A+=4.3\), \(A=4.0, A-=3.7, B+=3.3,\) and so on. Reading and grades (1.3) Write a few sentences comparing the distributions of English grades for light and heavy readers.

Short Answer

Expert verified
Heavy readers generally have higher English grades (higher median) and may show a narrower range of grades compared to light readers.

Step by step solution

01

Analyze the Boxplots

Examine the boxplots for both light and heavy readers. Note the key features, such as the median (shown by the line inside the box), the interquartile range (IQR, represented by the length of the box), whiskers, and any potential outliers (points outside the whiskers).
02

Compare Medians

Observe the median GPA for both groups. Identify which group has a higher median, indicating which group generally has higher English grades.
03

Compare Range and Spread

Compare the IQRs of both distributions. The IQR represents the middle 50% of the data, indicating which group's grades vary more or less.
04

Identify Outliers

Look for outliers in both groups as represented by dots or marks outside the whiskers. Note how these might affect the overall interpretation of the data.
05

Conclusion on Central Tendency and Spread

Summarize the similarities and differences in central tendencies (medians) and variabilities (IQR, range) of English grades between the two groups.

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Key Concepts

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

Boxplot Analysis
In statistics, a boxplot is a useful tool to visualize the distribution of data points. It provides insights into the central value, spread, and potential outliers of a dataset. Each boxplot consists of several components: the box itself, which represents the interquartile range (IQR); the line inside the box, which shows the median; and "whiskers" that extend to the smallest and largest values within 1.5 times the IQR. Analyzing these features helps us understand differences between groups, like light and heavy readers in our exercise. When comparing the boxplots of English grades for these two groups, we examine the medians to see which group generally scores higher. Also, paying attention to the spread of the data by analyzing the length of each box can tell us about the variability within each group. Finally, identifying any outliers (usually plotted as individual points) is crucial, as they can offer insights into unusual performance that deviates from the rest of the data.
Central Tendency
Central tendency refers to the measure that identifies the center of a dataset. In our exercise, the main focus is the median, which is prominently displayed in a boxplot. The median is the middle value when the data is ordered and is a robust measure of central tendency because it is less affected by extreme values compared to the mean. When comparing the central tendency of light and heavy readers, checking which group has a higher median provides information on which group typically performs better in English grades. The difference in medians helps answer the question if heavier reading correlates with higher grades. Analyzing this provides essential insights for educational strategies aiming to encourage reading habits.
Variability in Data
Variability in data highlights how spread out data points are around the central tendency. In the context of our exercise, the interquartile range (IQR) is the primary measure for this variability. The IQR covers the middle 50% of data, represented by the length of the box in a boxplot. Comparing the IQRs for light and heavy readers helps deduce which group has more consistency in their English grades. A smaller IQR indicates less variability, suggesting more uniform performance among students. Besides the IQR, examining any extreme data points, or outliers, visible beyond the whiskers of the boxplots, provides an additional layer to understand variations within each group. Combined, these analytical insights into variability assist in interpreting the stability of academic performance across different reading habits.
Correlation between Reading and Grades
Understanding the correlation between reading habits and academic performance is essential in educational analysis. In this exercise, we explore whether there's a significant relationship between how often students read for pleasure and their English grades. The boxplot comparison of light and heavy readers serves as our visual evidence. If heavier readers consistently exhibit higher medians, this suggests a positive correlation between reading frequency and English grades. However, correlation does not imply causation, so it's crucial to consider other factors that might contribute to better academic performance. Nevertheless, identifying such trends is valuable for educators when designing interventions to enhance students' reading habits possibly leading to improved academic outcomes.

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Most popular questions from this chapter

Refer to the following setting. The manager of a high school cafeteria is planning to offer several new types of food for student lunches in the following school year. She wants to know if each type of food will be equally popular so she can start ordering supplies and making other plans. To find out, she selects a random sample of 100 students and asks them, "Which type of food do you prefer: Asian food, Mexican food, pizza, or hamburgers?" Here are her data: $$ \begin{array}{lcccc} \hline \text { Type of Food: } & \text { Asian } & \text { Mexican } & \text { Pizza } & \text { Hamburgers } \\ \text { Count: } & 18 & 22 & 39 & 21 \\ \hline \end{array} $$ (a) \(\frac{(18-25)^{2}}{25}+\frac{(22-25)^{2}}{25}+\frac{(39-25)^{2}}{25}+\frac{(21-25)^{2}}{25}\) (b) \(\frac{(25-18)^{2}}{18}+\frac{(25-22)^{2}}{22}+\frac{(25-39)^{2}}{39}+\frac{(25-21)^{2}}{21}\) (c) \(\frac{(18-25)}{25}+\frac{(22-25)}{25}+\frac{(39-25)}{25}+\frac{(21-25)}{25}\) (d) \(\frac{(18-25)^{2}}{100}+\frac{(22-25)^{2}}{100}+\frac{(39-25)^{2}}{100}+\frac{(21-25)^{2}}{100}\) (e) \(\frac{(0.18-0.25)^{2}}{0.25}+\frac{(0.22-0.25)^{2}}{0.25}+\frac{(0.39-0.25)^{2}}{0.25}\) \(+\frac{(0.21-0.25)^{2}}{0.25}\) The chi-square statistic is

Multiple choice: Select the best answer for Exercises 19 to 22 Exercises 19 to 21 refer to the following setting. The manager of a high school cafeteria is planning to offer several new types of food for student lunches in the following school year. She wants to know if each type of food will be equally popular so she can start ordering supplies and making other plans. To find out, she selects a random sample of 100 students and asks them, "Which type of food do you prefer: Asian food, Mexican food, pizza, or hamburgers?" Here are her data: $$ \begin{array}{lcccc} \hline \text { Type of Food: } & \text { Asian } & \text { Mexican } & \text { Pizza } & \text { Hamburgers } \\ \text { Count: } & 18 & 22 & 39 & 21 \\ \hline \end{array} $$ An appropriate null hypothesis to test whether the food choices are equally popular is (a) \(H_{0}: \mu=25,\) where \(\mu=\) the mean number of students that prefer each type of food. (b) \(H_{0}: p=0.25,\) where \(p=\) the proportion of all students who prefer Asian food. (c) \(H_{0}: n_{A}=n_{M}=n_{P}=n_{H}=25,\) where \(n_{A}\) is the number of students in the school who would choose Asian food, and so on. (d) \(H_{0}: p_{A}=p_{M}=p_{P}=p_{H}=0.25,\) where \(p_{A}\) is the proportion of students in the school who would choose Asian food, and so on. (e) \(\quad H_{0}: \hat{p}_{\mathrm{A}}=\hat{p}_{M}=\hat{p}_{P}=\hat{p}_{H}=0.25,\) where \(\hat{p}_{\mathrm{A}}\) is the pro- portion of students in the sample who chose Asian food, and so on.

Exercises 59 to 60 refer to the following setting. For their final project, a group of AP \(^{\otimes}\) Statistics students investigated the following question: "Will changing the rating scale on a survey affect how people answer the question?" To find out, the group took an SRS of 50 students from an alphabetical roster of the school's just over 1000 students. The first 22 students chosen were asked to rate the cafeteria food on a scale of 1 (terrible) to 5 (excellent). The remaining 28 students were asked to rate the cafeteria food on a scale of 0 (terrible) to 4 (excellent). Here are the data: $$ \begin{array}{lcccrc} &{1 \text { to 5 scale }} \\ \text { Rating } & 1 & 2 & 3 & 4 & 5 \\ \text { Frequency } & 2 & 3 & 1 & 13 & 3 \\ \hline & {0 \text { to 4 scale }} \\ \text { Rating } & 0 & 1 & 2 & 3 & 4 \\ \text { Frequency } & 0 & 0 & 2 & 18 & 8 \\ \hline \end{array} $$ Average ratings (1.3,10.2) The students decided to compare the average ratings of the cafeteria food on the two scales. (a) Find the mean and standard deviation of the ratings for the students who were given the 1 -to- 5 scale. (b) For the students who were given the 0 -to- 4 scale, the ratings have a mean of 3.21 and a standard deviation of \(0.568 .\) Since the scales differ by one point, the group decided to add 1 to each of these ratings. What are the mean and standard deviation of the adjusted ratings? (c) Would it be appropriate to compare the means from parts (a) and (b) using a two-sample \(t\) test? Justify your answer.

You may find the inference summary chart inside the back cover helpful. Inference recap \((8.1\) to 11.2\()\) In each of the following settings, state which inference procedure from Chapter \(8,9,10,\) or 11 you would use. Be specific. For example, you might say "two-sample \(z\) test for the difference between two proportions." You do not need to carry out any procedures. \(^{30}\) (a) Is there a relationship between attendance at religious services and alcohol consumption? A random sample of 1000 adults was asked whether they regularly attend religious services and whether they drink alcohol daily. (b) Separate random samples of 75 college students and 75 high school students were asked how much time, on average, they spend watching television each week. We want to estimate the difference in the average amount of \(\mathrm{TV}\) watched by high school and college students.

Skittles Statistics teacher Jason Molesky contacted Mars, Inc., to ask about the color distribution for Skittles candies. Here is an excerpt from the response he received: "The original flavor blend for the SKITTLES BITE SIZE CANDIES is lemon, lime, orange, strawberry and grape. They were chosen as a result of consumer preference tests we conducted. The flavor blend is 20 percent of each flavor." (a) State appropriate hypotheses for a significance test of the company's claim. (b) Find the expected counts for a bag of Skittles with 60 candies. (c) How large a \(\chi^{2}\) statistic would you need to have significant evidence against the company's claim at the \(\alpha=0.05\) level? At the \(\alpha=0.01\) level? (d) Create a set of observed counts for a bag with 60 candies that gives a \(P\) -value between 0.01 and \(0.05 .\) Show the calculation of your chi-square statistic.

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