Same Science › Working with data › Data tables and averaging trials
How do kids use data tables and averages?
Lab results go in a data table: the independent variable in the first column, then one column per trial of the dependent variable, then the mean. To find the mean, add the trials and divide by how many there are. If one trial is far off from the others (an outlier), many classes note it and average without it.
- First column: what you changed.
- Mean: add the trials, divide by how many.
- An outlier is a result far from the others.
Why schools teach it
Making results trustworthy
Students organize data and use math to analyze it (NGSS science practices 4 and 5), and sixth graders summarize data with the mean (6.SP.B.5).
Averaging trials is why scientists repeat experiments: one odd trial can't swing the conclusion.
At the kitchen table
What to say, and what to skip
Say this
What goes in the first column?
The independent variable.How do you find the mean?
Add the trials, divide by the number of trials.Is any trial way off from the others?
That might be an outlier.What pattern do you see in the means?
Skip this
- Dividing by the wrong number.Three trials: divide by 3.
- Deleting results you don't like.Note an outlier and explain why; don't hide it.
- Forgetting units in the headings.“Distance (cm)” in the header covers the whole column.
See it in action
Averaging 96, 91 and 95 cm
Add the trials
96 + 91 + 95 = 282Divide by the number of trials
282 ÷ 3 = 94Record it
Mean: 94 cm
If the mean isn't a whole number, round to the nearest tenth.
Free practice sheet
Make a data table sheet
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Parents also ask
Is the mean the same as the average?
Yes. Mean is the math word for average.
What's an outlier?
A result much higher or lower than the others, often from a mistake like a timer started late.
Should the outlier be removed?
Many classes average with and without it and explain. Follow the teacher's rule.
How many trials should there be?
At least three is the usual classroom rule.