Reporting Chemical Data: Statistics, Figures and Data Availability · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Report results others can build on

Science · Chemistry · ages 23-24
Name ______________________   Date ____________

  1. Two groups with the same mean must have the same spread of points.

    Circle one:   True   False

  2. A chemist weighs the same powder sample three times and gets 2.41 g, 2.45 g, and 2.43 g. What is the mean of the three measurements, in grams? Give your answer to two decimal places.

    Answer: ______________

  3. What should accompany every reported result?

    • Replicates and a matching uncertainty
    • The best single run, to two decimals
    • A mean with as many decimals as possible

  4. Open sharing lets others check calculations, redraw figures, and repeat experiments.

    Circle one:   True   False

  5. Which raw files should you deposit for a stated result?

    • Only the polished summary table
    • The readings behind it, in usable form
    • An unrelated older dataset

  6. True or false: when two groups are compared, like fuel efficiency of manual and automatic cars, reporting only the two means without the group sizes or the spread is enough for a reader to judge the conclusion.

    Circle one:   True   False

  7. Three runs of a synthesis give yields of 72%, 75% and 78%. Which report is complete?

    • 75%, the average of the runs
    • Between 72% and 78%
    • 75% ± 3% (SD, n = 3)
    • 78%, from the best of the three runs

  8. A results section gives single yields with no uncertainties. What do you ask for?

    • Fewer significant figures only
    • The single best yield per entry
    • Replicates with uncertainties

  9. Two labs clash over one mean each, both hiding points. What resolves it?

    • Averaging the two means
    • Trusting the lab with more papers
    • Each lab's raw points and errors

  10. Depositing only the polished table counts as sharing data others can build on.

    Circle one:   True   False

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Answer key

For grown-ups. Fold this page away before handing over the rest.

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  1. False · Two groups can share a mean while one is tightly bunched and the other is widely scattered. Only plotting the points shows the difference.
  2. 2.43 · The mean is the sum of the measurements divided by how many there are. Reporting the mean together with the number of repeats is the first step toward an honest result.
  3. Replicates and a matching uncertainty · Repeats and uncertainty say how firm the number is.
  4. True · Reachable raw files make checking possible at all.
  5. The readings behind it, in usable form · Retracing needs the readings, not the polish.
  6. False · Without knowing how many observations went into each group and how scattered they were, a reader cannot tell whether a difference between means is real or just luck.
  7. 75% ± 3% (SD, n = 3) · A complete report gives the mean, the spread and the number of runs: 75% with a standard deviation of 3% from 3 runs.
  8. Replicates with uncertainties · Single numbers with no backing cannot be built on.
  9. Each lab's raw points and errors · Visible spreads plus files show whether the means even disagree.
  10. False · Strangers need the readings to retrace and extend the work.
Worksheet · LightMySky