Week 2 — Is This Chart Honest? A Short Data-Display Report — Traditional alternative (no AI)

Instructors: publish this instead of the adaptive version if you prefer, and unpublish or delete the adaptive one.

Assignment 2 of the term — read a table and three graphs built from real data, check them for honesty, and explain your choice of chart to someone new to statistics.

This week you learned to turn a long list of values into a table and a picture, to name a picture's shape by its tail, and to catch a graph drawn to mislead. Last week you sorted variables as categorical or quantitative; this week that sorting decides which display each variable gets. In this assignment you work four short problems on real data, interpret each one, and explain a chart choice to someone who has never studied statistics. This week's lecture tutorial, quiz, discussion, and Data Lab practise the same ideas from other angles.

The task

The Palmer penguins field log is a real observational dataset of 344 penguins: 152 Adelie, 68 Chinstrap, and 124 Gentoo, logged on three islands. In the species-by-island table, the Adelie were logged on Biscoe (44), Dream (56), and Torgersen (52); all 68 Chinstrap were on Dream; and all 124 Gentoo were on Biscoe. The 342 penguins with a recorded body mass weigh from 2,700 g to 6,300 g. You will also use the calendar: the 12 months of a common year have 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, and 31 days.

Work these four problems, showing your arithmetic:

1. In the species-by-island table, the Dream column holds 56 Adelie and 68 Chinstrap penguins. How many penguins were logged on Dream?
2. The 342 measured penguin body masses run from 2,700 g to 6,300 g. A histogram uses bins 500 g wide, starting at 2,500 g and ending at 6,500 g. How many bins does it have?
3. The middle value of the 342 penguin body masses is 4,050 g, and their average is 4,201.75 g. By how many grams does the average exceed the middle value?
4. A bar chart of month lengths starts its vertical axis at 26 days. How many times taller does a 31-day month's bar look than February's 28-day bar?

Beside each answer, add one brief interpretation: what that value shows about the table or graph, and one use or limit of it. For problem 3, name the shape of the body-mass distribution by its tail. For problem 4, say how big the real gap between the two months is.

Show your arithmetic. A reader should be able to reproduce every number you report from the values above without guessing which values or steps you used.

Explain it to a non-expert

The volunteer editor of a community nature-center newsletter has never studied statistics and wants to print one chart of the penguin species counts. Write a 3–5 sentence message that recommends a chart for the species counts, gives a reason tied to these data, and names one limit — for example, that the bars must start at zero so no species looks smaller than it is, or that the field log is an observational study, so the chart describes the penguins but cannot show why the species differ. Explain any technical term in everyday words. More than one recommendation can be defensible.

For a different, ungraded example, imagine a farmers-market manager who wants to show how many shoppers visited on each day of the week. Model answer: "I'd use a simple bar chart with one bar per day, starting the scale at zero. That way a slow day looks only as slow as it really was, and you can compare days at a glance. It shows when people came, but not why, so it can't tell us whether the new music caused a busier Saturday."

Use that pattern for the penguins, with your own recommendation and evidence.

Deliverables

Submit a single data-display report containing:

• the four answers, each with the arithmetic shown and a brief interpretation of what that value shows about the table or graph and one use or limit of it;
• your message to the editor, recommending a chart for the species counts with a reason tied to these data and naming one limit; and
• a one-line restatement of the values you used, so your results are reproducible.

Keep it to roughly one page. Clear and correct beats long.

Choose how you show it. Present your report as written text, or as a recorded audio or video explanation of about three minutes with a transcript, or as a labelled sketch of the charts with a short note. Every form is graded by the same scoring criteria. Submit in any accessible file type or as a link; a recorded response may be submitted as audio or video with a transcript, or as text.

How you'll be graded

The full analytic rubric is attached to this assignment in Canvas.

Academic integrity and AI use

This version is designed to be completed without AI: do the computations, the interpretations, and the writing yourself, without a chatbot or other AI tool. You may use a calculator or a spreadsheet for the arithmetic. Submitting AI-generated work as your own, or copying another student's numbers, is an integrity violation under the course policy.

Built with The Course Maker · samples.thecoursemaker.com