Estimate a population mean

Estimate the uncertainty in a mean from a sample size, mean and standard deviation.

Guides · Basic statistics · 4 min read

Example: Cell A mean seal strength

45 independent pouch-strength readings from Cell A; the reference CSV also contains 45 readings from Cell B.

Download the study reference (CSV)

This is the same example used in Help. The CSV is a reference for the supplied study. Enter the checked summaries manually on Inputs; importing the CSV does not populate this calculator. Use Open example in a practice copy in Help to prefill the inputs.

1. Create the workspace

In the sidebar, open Basic Statistics and choose Confidence Intervals. Create an analysis, name it, select New blank worksheet, then choose Create analysis.

2. Choose the interval

On Inputs, choose Mean (t) for Parameter. Enter 0.95 in Confidence level (0–1) for a 95% interval.

3. Enter the summaries

Under Summarized data, enter the following values. Keep the full precision shown for means and standard deviations. No worksheet columns are assigned.

Enter 45 in Sample size (n).

Enter 17.988222222222223 in Sample mean (x̄).

Enter 1.053112894079627 in Sample standard deviation (s).

Confidence Intervals: Inputs with the example’s assignments and settings
Inputs with the selected population parameter, 95% confidence level and entered sample summaries. View full-size image (opens in a new tab)

4. Run analysis

Choose Run analysis, then open Results.

5. Interpret results

  1. Identify what the interval estimates

    45 independent pouch-strength readings from Cell A; the reference CSV also contains 45 readings from Cell B. The selected parameter is mean (t).

  2. Read the estimate and bounds

    The Cell A sample mean is 17.9882 N. The 95% confidence interval for the population mean is 17.6718–18.3046 N.

  3. Keep the interpretation clear

    This interval concerns the average strength, not the range of individual pouch strengths. It uses a t-based model for independent measurements.

  4. Use the uncertainty in the decision

    Compare the whole interval with a defined mean-strength requirement. If its width is too large for the decision, plan additional representative measurements.

More details: read each result section

Complete result tables use six significant digits, as in Help.

Confidence interval

Parameter names the population quantity. Confidence level 0.95 means this interval method covers the fixed population parameter in 95% of repeated comparable samples under its assumptions. Estimate is the sample-based value; Lower bound and Upper bound mark its uncertainty. Method records the calculation. This interval concerns the average strength, not the range of individual pouch strengths. It uses a t-based model for independent measurements.

Confidence interval · 6 rows
StatisticValue
ParameterMean (t)
Confidence level0.95
Estimate17.9882
Lower bound17.6718
Upper bound18.3046
Methodt-based

6. Create a report

Keep the complete Confidence interval table, selected parameter, confidence level, method and entered summaries. This interval concerns the average strength, not the range of individual pouch strengths. It uses a t-based model for independent measurements.

Choose Add to report from the completed run. Open Choose individual items and advanced options to select tables and charts, then choose Add to draft. Hidden items stay in the saved analysis.

Name the report and add the purpose of the study and your interpretation. Choose Save, review Preview, then use Export → Download HTML. The example below contains the full selected content, including results beyond one screen.

Complete native output for this Help example, including applicable tables, charts and run notes. Report numbers use the app’s displayed precision. Exported charts are static. On narrow screens, scroll wide charts and tables sideways.
View example report: Estimate mean seal strength

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