10.2.2: TL 2
- Page ID
- 63693
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)Tech Lab 2 – Measures of Center, Variation, Boxplots, and Quartiles
Purpose
In this technology lab, you will use Excel to compute descriptive statistics, five-number summaries, and create boxplots. You’ll also learn how to interpret measures like the mean, median, range, and standard deviation in the context of real data.
Descriptive Statistics – Measures of Center and Variation
In class, we’ll review Excel functions to compute mean, median, and mode. You can also follow along with this video: Measures of Center Use the chapter time stamps in the video to jump to specific parts in Excel.
To compute range and standard deviation, Excel provides built-in functions. Note that there are different functions depending on whether you're calculating for a sample or a population
Practice with Descriptive Stats:
Download the “Anonymous Survey Data” from the course module and save a copy on your computer or OneDrive.
- Find the mean, median, range, and standard deviation for two columns:
- “Number of hours of sleep you got last night”
- “Number of pets you have”
- Compare the mean and median for each.
- Are they close together or different?
- Is the mean larger than the median or vice versa?
- How might this help you infer the skew of the data?
- Standard deviation is often used to describe a “typical range” of values or to flag unusual values.
- Compute:
- mean ± standard deviation
- mean ± 2 × standard deviation
- Interpret:
- Is your own number of hours of sleep in the “typical” range?
- Do any class sleep values fall outside the “unusual” range?
- Compute:
Five-Number Summary & Boxplots
Excel can calculate five-number summaries using these formulas:
- Minimum:
=MIN(range) - Q1:
=QUARTILE.INC(range, 1) - Median:
=MEDIAN(range) - Q3:
=QUARTILE.INC(range, 3) - Maximum:
=MAX(range)
Excel can also automatically create a modified boxplot. Use this guide to get started: 5 Number Summary and Boxplots in Excel 365 (11:07). For more background knowledge, check out: 5 Number Summary and Boxplots Explained (14:52).
🧪 Practice with Boxplots:
- Compute the five-number summary for the “Number of Pets” column.
- Create a boxplot in Excel. Double-check that the five-number summary matches the visual graph. Add:
- A clear, descriptive title
- Labeled axes if possible
- Interpret your boxplot:
- What values make up the lower 25% of the data? (Between min and Q1)
- What range makes up the middle 50%? (Interquartile Range from Q1 to Q3)
- What range makes up the upper 25%? (Q3 to max)
- Does the boxplot show skew to the left or right? Justify your answer based on the shape and whiskers.
Interpreting a Published Boxplot
Review the following image from A Guide to R for Social and Behavioral Science Statistics by Brian Joseph Gillespie. It shows side-by-side boxplots comparing number of siblings for two groups:
- Top boxplot: people who have children
- Bottom boxplot: people who do not have children
The dots (●) represent outliers. While you can’t determine exact values or the number of data points from a boxplot, you can describe the distribution shape, spread, and central tendencies visually.
Written Reflection:
Write a short paragraph that addresses the following:
- What does each group’s boxplot tell us about the number of siblings?
- Which group seems to have more variability?
- How do the median values compare?
- What comparisons and trends can you draw across the two groups?
Submission Instructions
- Include: your descriptive stats, 5-number summary, boxplot(s), and written responses in one Excel file or Word doc
- File name:
LastName_TechLab2.xlsxorLastName_TechLab2.docx - Submit via the Tech Lab folder on the course LMS