September 14, 2026
Summarize · Week 04
Descriptive statistics with R
Finish the R-fundamentals sequence with vectors, data frames, and functions, then use R to summarize what is typical, measure variation, and select observations for a focused analysis.
Sep 14–18Lecture 3, slide 31 → Lecture 4Homework 1
ImportantWeek 4 sequence
- Resume Lecture 3 at slide 31: ➡️ A vector stores values of one type, and continue through slide 42.
- Use Classwork 2 to practice the R fundamentals.
- Begin Lecture 4: Descriptive Statistics with R at its title slide.
- Begin Homework 1.
Focus
- Vectors, data frames, factors, and type conversion
- Functions, arithmetic, and vectorized operations
- Center, spread, boxplots, and vector selection
Prepare
- Open Lecture 3 at slide 31
- Bring Classwork 2 and your R script
- Open your section’s project in Posit Cloud
Practice
- Create and inspect vectors and data frames
- Use functions and vectorized operations
- Calculate and interpret descriptive summaries
Learning targets
- Create vectors and explain why one vector stores values of a common type.
- Explain how vectors, factors, and data frames organize values in R.
- Read function calls and use vectorized arithmetic.
- Explain what descriptive statistics reveal—and what they cannot establish alone.
- Choose among mean, median, and mode for a particular variable and question.
- Calculate and interpret range, variance, standard deviation, quartiles, and IQR.
- Read a boxplot as a summary of quartiles, spread, and possible outliers.
- Select vector values using positions, vectors of positions, and logical conditions.
Tip
A summary starts the investigation; it does not replace the original data. Interpret every statistic in the context of the variable and question.
Lecture slides
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