Speed Reading Jessica enrolled in a course that promised to increase her reading speed. To help judge the effectiveness of the course, Jessica measured the number of words per minute she could read prior to enrolling in the course. She obtained the following five-number summary: 110 140 157 173 205. Use this information to draw a boxplot of the reading speed.
Table of contents
- 1. Intro to Stats and Collecting Data1h 14m
- 2. Describing Data with Tables and Graphs1h 55m
- 3. Describing Data Numerically2h 5m
- 4. Probability2h 16m
- 5. Binomial Distribution & Discrete Random Variables3h 6m
- 6. Normal Distribution and Continuous Random Variables2h 11m
- 7. Sampling Distributions & Confidence Intervals: Mean3h 23m
- Sampling Distribution of the Sample Mean and Central Limit Theorem19m
- Distribution of Sample Mean - Excel23m
- Introduction to Confidence Intervals15m
- Confidence Intervals for Population Mean1h 18m
- Determining the Minimum Sample Size Required12m
- Finding Probabilities and T Critical Values - Excel28m
- Confidence Intervals for Population Means - Excel25m
- 8. Sampling Distributions & Confidence Intervals: Proportion1h 25m
- 9. Hypothesis Testing for One Sample3h 29m
- 10. Hypothesis Testing for Two Samples4h 50m
- Two Proportions1h 13m
- Two Proportions Hypothesis Test - Excel28m
- Two Means - Unknown, Unequal Variance1h 3m
- Two Means - Unknown Variances Hypothesis Test - Excel12m
- Two Means - Unknown, Equal Variance15m
- Two Means - Unknown, Equal Variances Hypothesis Test - Excel9m
- Two Means - Known Variance12m
- Two Means - Sigma Known Hypothesis Test - Excel21m
- Two Means - Matched Pairs (Dependent Samples)42m
- Matched Pairs Hypothesis Test - Excel12m
- 11. Correlation1h 24m
- 12. Regression1h 50m
- 13. Chi-Square Tests & Goodness of Fit2h 21m
- 14. ANOVA1h 57m
3. Describing Data Numerically
Boxplots
Problem 3.5.2
Textbook Question
In a boxplot, if the median is to the left of the center of the box and the right whisker is substantially longer than the left whisker, the distribution is skewed ______________.
Verified step by step guidance1
Understand the components of a boxplot: the box represents the interquartile range (IQR), the line inside the box is the median, and the whiskers extend to the smallest and largest data points within 1.5 times the IQR from the quartiles.
Note that if the median is to the left of the center of the box, it means the median is closer to the first quartile (Q1) than to the third quartile (Q3). This suggests that the lower half of the data is more tightly packed than the upper half.
Observe that the right whisker being substantially longer than the left whisker indicates that there is a longer spread or more extreme values on the higher end of the data.
Combine these observations: a median closer to the lower quartile and a longer right whisker typically indicate that the distribution has a longer tail on the right side.
Conclude that the distribution is skewed to the right (positively skewed) because the tail on the right side is longer and the bulk of the data is concentrated on the left.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Boxplot Components
A boxplot visually summarizes data using five key statistics: minimum, first quartile (Q1), median, third quartile (Q3), and maximum. The box represents the interquartile range (IQR) between Q1 and Q3, with a line inside indicating the median. Whiskers extend from the box to the smallest and largest data points within 1.5 times the IQR.
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Boxplots Example 1
Skewness in Distributions
Skewness describes the asymmetry of a data distribution. A distribution is right-skewed (positively skewed) if the tail on the right side is longer or fatter, and left-skewed (negatively skewed) if the left tail is longer. Skewness affects the position of the median relative to the quartiles and the length of whiskers in a boxplot.
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Sampling Distribution of Sample Mean
Interpreting Median and Whiskers in Boxplots
In a boxplot, if the median is closer to the left side of the box and the right whisker is longer, it indicates more spread or extreme values on the right side. This pattern suggests a right-skewed distribution, where the bulk of data is concentrated on the lower end with a tail extending to higher values.
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Boxplots ("Box and Whisker Plots")
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